Food Science (Scan)

Try This Hot-SpotExperiment

You can seewith your own eyeswhether a pan has hot spots. Moisten

'/4cup of sugor with°couple of tablespoons of water. Spread the mixtureuniformly on the Aat cooking surface ofa stainlesssteel pan (preferably thingauged). Thenturn the heat to a lowtomedium setting and wait for the sugarto startto caramelize. Ifyour pan has

no hotspots, the sugarwill caramelize

evenly. Ifithas hot spots, the sugor directlyover them will caramelize first,forming a patternthat mapsyour pan'shot spots.

cooking equipment . . 7

kitchenware in a dishwasher or on a drying rack also may not cutthe mustard.

Are hardwood spoons worth their higher price?

Hardwood spoons cost more than softwood spoons because theyare made of more expensive material and are more difficult tocarve. They absorb less bacteria and cooking flavors because theirwood is less porous. They are less likely to scorch, stain, crack, orwarp. They dry faster, are more attractive, and last more thantwice as long as softwood spoons.

Why is good heat distribution a virtue for a stove-top pan?

Unless heat can quickly spread through the entire bottom of apan, "hot" and "cold" spots will develop. The hot spots will be directly over the places wherethe heat source comes in contact with the pan. Thus, if thegas burner is starfish-shaped,or if the configuration of theelectric coil is a spiral, the hotspots will follow those patterns.

The problem of frying orbraising in a pan that has hotand cold spots is that youcannot cook the food properly- unless you do nothing elsebut constantly and thoroughly stir the contents (andwhen braising, you could notdo that even if you so desired).The food over the hot spotswill overcook. Or, if you lower the heat to prevent scorching, thefood will take longer to cook or there will probably be insufficientheat to cook the other portions of the food.

A knife be

comes dullerfaster on

polyethyleneboards thanon wood ones

chef's knife

Cross-Sectlcncl Views

slicing knife

What about doing the opposite, chopping firm food with a slicing knife? The chef's knife does a much better job because itswedge shape is broader on the top of its cross-section than theslicing knife. That extra weight gives the blade extra momentumand therefore more power to help the cook chop through firmfoods like garlic and carrots.

6 . . the new kitchen science

Should I buya wood orpolyethylene cutting board?

The harder a cutting surface, the more quickly a knife dulls. Hardsurfaces include metal, marble, china, crockery, enamel, glass,and most kitchen countertops. The softest, andtherefore the most desirable of the popular cutting surfaces, is wood. Though softwood doesless harm to the knife's edge, hardwood is usedmost often because it absorbs less moisture andlasts longer.

Polyethylene boards are not as hard as, say,. metal and glass,but they are harder than wood.Consequently, a knife becomes duller faster onpolyethylene boards than on wood ones. Even though polyethylene is easier to clean, most good cooks insist on wood cuttingboards because keeping a knife sharp is crucial.

Hard cutting surfaces are not the only anathema to a sharpknife blade. A blade that nicks too many bones or scrapes hard


dining room table. Unfortunately, its beauty is only "skin deep:'Enamelware (a misnomer) is a metal, not an enamel, pan. Theenamel is no more than a thin coating produced by fusing a powdered glass onto the metal (often cast-iron) pan in a kiln. Thissheer layer can chip easily if the cook accidentally bangs the panagainst the hard sink. Thermal shock is another hazard; a stovehot enamelware pot can shatter if the cook sets it in cold water.

Howdo nonstick snrfaces work?

Most nonstick kitchenware is made with chemically inert fluorocarbon plastic that is baked onto the cooking surfaces. These substances cover the pores and microscopic jagged peaks of the metal(usually aluminum) and therefore deny food the opportunity tolatch on to something.

Nonstick coatings in effect season the' pan. The commercial"seasoning" method produces a much slicker surface than thehome method-so slick that you can, if you want, fry foods withlittle or no oil or butter. .

What are the pros and cons ofnonstick coatings?

The nonstick surface is a blessing to people who must drasticallyrestrict their fat intake. However, for others, the main selling pointof the nonstick lining can turn out to be a drawback. When onecooks without oil or fat, the taste buds and olfactory receptors aredeprived of rich flavors that are essential to superb dining.

An indisputable positive feature of a nonstick pan is that itssmooth surface can be washed free of food quickly and with minimum effort. However, should metal utensils and scouring pads beused, they can easily scratch, making it more likely that food willstick to the pan. A nonstick lining also discolors with misuse, or intime, even with proper use. Too many of the nonstick coated pansare too thin and thus-because of the resulting uneven heat distribution - are not ideal for most stove-top cooking methods.

Finally, the nonstick coating is not truly nonstick C'low-stick"would be a better appellation), and its surface will eventually wear


away, despite what some kitchenware ads and salespeople profess.Generally, there is a correlation between how much you pay for apan and how long the nonstick surface will last.

Howdoes an anodized aluminum pan compare with a nonstickaluminum pan!

An anodized pan will likely be thicker gauged and better built but,like a nonstick pan, can be easily scratched and impaired by a careless cook or dishwasher. Both pans help prevent food from sticking' though the nonstick pan performs that mission demonstrablybetter. Unlike the nonstick variety, an anodized pan usually needsto be seasoned occasionally.

The anodization process is based on the principle that an oxidelayer forms naturally on alwninum and that this oxide helps prevent food from sticking to the metal. The thicker the layer, themore effective the defense. Manufacturers discovered that theycould artificially create a reasonably thick layer by means of electrolysis.

Why are pans that are constructedwith multi-plybottoms sohighly touted!

Their bottoms have three layers: a middle ply (generally aluminum) sandwiched between two stainless steel ones. The purposeof this design is to give the cook the best of both worlds by eliminating each metal's disadvantages.

The aluminum layer cannot become discolored, nor can itcolor or flavor foods, because it is completely enclosed within thestainless steel. The upper stainless steel layer does not have the hotspots that are common in 100 percent stainless steel pots, becauseby the time it reaches that stainless steel tier, the heat from theburner has been more or less evenly diffused by the aluminum(which is, unlike stainless steel, an excellent conductor of heat).And because the pan's entire metal surface is stainless steel, it hasan attractive shiny finish and is easier to clean. Still another bonus

18 . • the new kitchen science

Which is better, a gas or electric range?

A range (also called a stove-top) is the open cooking surface whereyou fry, saute, and boil foods. Most good cooks prefer a gas over anelectric range for reasons described later.

Which gas is better for range cooking, propane or natural gas?

Natural gas is superior. Propane generates 10 to 20 percent fewerBTUs than natural gas. This means, for instance, that propane willtake longer to boil a pot ofwater. And it more readily blackens thebottoms of pots and pans because it does not burn as cleanly asnatural gas.

Propane has its place. It fuels nearly all outdoor gas grills. Ifyoulive in a country home that is not connected to a natural gaspipeline-and you do not like the, alternative of cooking on anelectric range-then propane is the answer. Youwill need an outside propane tank and a range that can be converted to use propane.

What are the electric range options?

The two basic electric range categories are coil and cook-top.The electric coil variety uses a spiral heating element that sits

exposed on top of the range. This device heats and responds totemperature adjustments very slowly. It is difficult to clean. It ismore likely to malfunction than other range types. Avoid electriccoil ranges, even though they are the least expensive range.

An electric cook-top is a flat, smooth-surfaced range. The heating units lie hidden under the glass-ceramic panel. There are several electric cook-top subcategories: radiant, halogen, and induction.

What are the pros and cons of the three cook-top types?

You need a range that can be adjusted in small increments and canrespond qnickly to any heat adjustment. That is crucial when, forinstance, something starts to boil that shouldn't. The range mustalso heat food reasonably fast.

cooking equipment • • 19

The original radiant cook-tops disappointingly botched theabove duties. Although ribbon-style radiant cook-tops do better,they still do not perform those jobs as well as the halogen and induction cook-tops. And their cooking area remains hot long afterthe pan is removed-a hazard.

Halogen cook-tops produce the cooking heat with a halogenbulb. Like radiant cook-tops, they heat the cook-top, which heatsthe pan, which heats the food. Because they become a great dealhotter than a radiant cook-top, they are even more hazardous.

Induction cook-tops heat a pan directly by means of a magnetic field. They do not heat the glass-ceramic panel that lies between the pan and the magnetic induction device. When you remove a pan, the cook-tap's cooking area is not hot. What warmthit has comes from the heat conducted from the hot pan. Magneticinduction cook-tops heat and respond to temperature adjustments as fast as halogen and gas ranges. A major drawback is thatyou can use ouly pots and pans that contain a metal (like iron orsteel) that is responsive to magnetic fields.

Youcan purchase a mixed-unit cook-top. It is built with a combination of radiant, halogen, and/or induction heating units.

Because of their flat surfaces, all cook-tops are easier to cleanthan gas and electric-coil cook-tops. However, it is expensive to replace a glass-ceramic cook-top that has been broken by an accidentally dropped pan. Moreover, a pan has to be perfectly flat foroptimum cooking on the smooth cook-top. Gas burners-because they cook with flames-are more forgiving if the pan's bottom is dented or warped. Another advantage of gas is that you cansee the flames, which help you estimate without uncovering a potthe intensity of the heat that is being applied to the food.

Overall, most good cooks cast their vote for a gas range. Thosewho prefer electric ranges are partial to magnetic induction cook

tops.

or electric oven broiler?

The electric oven wins hands down. Electricity is by far the bestenergy source for the oven-broiler unit, for many reasons. An elec-


Which is better, a gas or electric range?

A range (also calleda stove-top) is the open cooking surface whereyou fry,saute, and boil foods. Most good cooks prefer a gas over anelectric range for reasons described later.

Which gas is better for range cooking, propane or natural gas?

Natural gas is superior. Propane generates 10 to 20 percent fewerBTUsthan natural gas. This means, for instance, that propane willtake longer to boil a pot ofwater. And it more readily blackens thebottoms of pots and pans because it does not burn as cleanly asnatural gas.

Propane has its place. It fuels nearly all outdoor gas grills. If youlive in a country home that is not connected to a natural gaspipeline-and you do not like the alternative of cooking on anelectric range-then propane is the answer.Youwill need an outside propane tank and a range that can be converted to use propane.

What are the electric range options?

The two basic electric range categories are coil and cook-top.The electric coil variety uses a spiral heating element that sits

exposed on top of the range. This device heats and responds totemperature adjustments very slowly. It is difficult to clean. It ismore likely to malfunction than other range types. Avoid electriccoil ranges, even though they are the least expensive range.

An electric cook-top is a flat, smooth-surfaced range. The heating units lie hidden under the glass-ceramic panel. There are several electric cook-top subcategories: radiant, halogen, and induction.

What are the pros and cons of the three cook-top types?

Youneed a range that can be adjusted in small increments and canrespond quickly to any heat adjustment. That is crucial when, forinstance, something starts to boil that shouldn't. The range mustalso heat food reasonably fast.


The origlnal radiant cook-tops disappointingly botched theabove duties. Although ribbon-style radiant cook-tops do better,they still do not perform those jobs as well as the halogen and induction cook-tops. And their cooking area remains hot long afterthe pan is removed-a hazard.

Halogen cook-tops produce the cooking heat with a halogenbulb. Like radiant cook-tops, they heat the cook-top, which heatsthe pan, which heats the food. Because they become a great dealhotter than a radiant cook-top, they are even more hazardous.

Induction cook-tops heat a pan directly by means of a magnetic field. They do not heat the glass-ceramic panel that lies between the pan and the magnetic induction device. When you remove a pan, the cook-top's cooking area is not hot. What warmthit has comes from the heat conducted from the hot pan. Magneticinduction cook-tops heat and respond to temperature adjustments as fast as halogen and gas ranges. A major drawback is thatyou can use only pots and pans that contain a metal (like iron orsteel) that is responsive to magnetic fields.

Youcan purchase a mixed-unit cook-top. It is built with a combination of radiant, halogen, and/or induction heating units.

Because of their flat surfaces, all cook-tops are easier to cleanthan gas and electric-coil cook-tops. However, it is expensive to replace a glass-ceramic cook-top that has been broken by an accidentally dropped pan. Moreover, a pan has to be perfectly flat foroptimum cooking on the smooth cook-top. Gas burners-because they cook with flames-are more forgiving if the pan's bottom is dented or warped. Another advantage of gas is that you cansee the flames, which help you estimate without uncovering a potthe intensity ofthe heat that is being applied to the food.

Overall, most good cooks cast their vote for a gas range. Thosewho prefer electric ranges are partial to magnetic induction cooktops.

Which is better, a gas or electric oven broiler?

The electric oven wins hands down. Electricity is by far the bestenergy source for the oven-broiler unit, for many reasons. An elec-


tric oven reaches the desired temperature more quickly,and if theoven has cooled because the cook opened the door, it regains theprogrammed temperature in less time. Generally, an electric ovenis more accurate (particularly at low temperature settings) andmaintains a relativelysteady temperature. (Many gas ovens, unlessturned on full blast, fluctuate by 25°F or more around the programmed temperature in a roller-coaster fashion.) Many electricovens are self-cleaning because they can reach a very high temperature. Since the broiler is built into an electric oven, it is easier toreach and can accommodate thicker foods. Finally, an electricoven heatsthe kitchen less (a boon when the room is hot; not sowhen it is cold).

Can I have the best ofboth worlds- a gas range and an electricoven broiler?

Although virtually all single-unit range-oven-broiler systemsmade for home use are either the all-gas or all-electric variety, youcan buy a gas range and electric oven-broiler unit separately. Thefirst snugly fits into a hole cut into your counter. The second is installed in a wall cabinet or under a counter (but not directly underthe separately installed range because of space limitations). Go forthe dual system the next time you remodel your kitchen.

Is a convection oven better than a traditional one?

Both the convection and traditional ovens depend on convectionheating. The salient difference between the two is that the convection oven uses the principle of convection more effectively. It hasa built-in electric fan that increases the circulation of hot airmolecules within the oven. This increase in air circulation is aboon when you roast meat or bake breads and pastry (but has noeffect on covered foods). Since the oven temperature is uniformthroughout, the food's surface will be more eveuly cooked andbrowned (though the outside of a meat does not develop as appealing a crusty texture). Another advantage of the convectionoven is that it reduces the required temperature and cooking time


and therefore meat shrinks less. Furthermore, most meats do notrequire basting, and so the cleanup chore is less bothersome because there is less splatter. Energy cost savings are often realizedbecause ofthe unit's efficiencyand generally more compact size.

comblnes the convection and

The combined oven makes sense if you are short on kitchen space.Bear in mind that when a manufacturer builds a convection ovensystem into a traditional oven, the oven's interior dimensionsshrink.

a pressure cookerworthwhile?

For someone who lives at a high altitude or who cans and preserves foods, a pressure cooker is an asset. In Denver, for instance,water boils at 203°Finstead of212°F, as it would, say,in San Diego.Consequently, any given ingredient takes.longer to cook in Denver. The predicament of having a relatively low boiling point forwater can be solved with a pressure cooker, since it allowswater toreach a temperature ofup to about 250°F.

Water inside a pressure cooker boils at a high temperature because the atmospheric pressure within the pot is increased. Theingredients also cook faster because the steam-most of which

not escape the pot-is a better heat conductor than air. Andth.n1« to the increased pressure within the pot, that steam moreaggressively penetrates the food.

The higher temperatures of pressure-cooking also benefit thecanner because the heat can more effectively destroy the

pathogenic microorganisms that contaminate the food. This canoc';tv;< particularly critical when canning low-acid ingredients.

For other cooks, a pressure cooker can shorten the cookingprocess and thereby reduce fuel expenditure, compared with thenonpressurized boiling method. From a gourmet's viewpoint,however, the texture of pressure-cooked foods like meat still resembles that ofordinary boiled food.


Why are budget-priced food processors seldom a good value?

If you are planning to use your food processor only for tasks thatrequire relatively little power (such as slicing a cucumber or othersoft vegetable), then a budget-priced model may serve your purposes. Chances are, however, that you also want your machine toperform more arduous chores, like chopping meat, in which case abudget model is no bargain.

A key reason that a budget-priced food processor is ill suited forchopping foods like meat is that it does not have enough horsepower. If the motor is not powerful enough, it is apt to balk momentarily, or even permanently, when you process a heavy load.

Another reason for poor performance is that nearly all budgetpriced models are belt-driven. (In other words, the motor turns abelt, which turns the cutting-blade unit) The belts in inexpensivemodels tend to slip when you process a heavy load. This problemdoesn't occur when the motor's drive shaft directly rotates the cutting blade, as is the case with most of the better processors.

Motor-balking and belt slippage are major mechanical deficiencies because they make it impossible to chop a batch of fooduniformly. What inevitably happens in the case of beef, for example, is that when some of the meat is properly chopped, the restof the meat is too lumpy (underchopped) or too pasty (overchopped). As good cooks know, a pasty grind guarantees a heavyand compact, and therefore inferior, meat loaf or hamburgerpatty.

Why is an electric deep-fat fryer unsuitable?

When deep-frying, you sometimes have to adjust the temperaturequickly. The conventional pan-on-a-flame method gives you reasonable flexibility, but with an electric deep-fat fryer there is toolong a lag between the time you reset the thermostat and the timethe oil reaches the desired temperature. Deep-frying with a pan onan electric range causes almost as much trouble as the electric panmethod.


Howdoes a microwave oven work?

A tube within the oven, called a "magnetron:' emits high-frequency electromagnetic waves (similar to radio waves). This radiation is scattered in the oven by a fanlike reflector (called the "stirrer"). When the waves penetrate the food, they reverse the polarityofthe water and other liquid molecules, billions oftimes a second.This oscillation causes the molecules to vibrate and bounceagainst each other. These collisions create friction and, as a byproduct, the heat that cooks or warms the food.

The microwave's heating element does not heat the circulatingair, the oven walls, or the vessel holding the food. When a bowl orplate becomes warm in a microwave oven, either it absorbed theheat from the cooking food or the surface of the vessel not touching the food was wet before the oven was turned on.

..lIli.....rethe: pros and cons ofmicrowave cooking?

Speed is the name of the game in microwave cookery. Most foodscook in one-quarter to one-half the time that other basic cookingmethods require because the food cooks from within. Microwavecooking costs less because it requires about one-quarter the powerthat a traditional oven uses. A microwave oven also causes lesssplatter and hardly heats up the kitchen.

Baked goods rise higher in a microwave oven. On the otherhand, bread, rolls, and other baked goods do not brown as well asthey do in a traditional oven. Neither does meat, which means itwon't develop the desirably flavorful crust caused by the Maillard(browuing) reaction (see p. 33). Some microwave producers dealwith this problem byadding convection fans and electrical heatingelements. These devices do work, but their results pale comparedto those ofdedicated conventional and convection ovens.

Cooks face other problems as well. Microwave cooking tends togive meats a dry, mushy texture. It's also harder to predict theproper cooking time, especially for a large cut of meat-, Consequently, microwaved food is more likely to come out of the ovenundercooked or overcooked.


parts. This creates two of the benefits mentioned earlier in theQ&A on ground chuck (see p. 63). The extra fat adds extra flavor,and because the fat-to-water ratio is higher, less water will exudout of the meat into the frying pan. Better browning and lesplattering result. On the other hand, the loin-end chop has its adherents because it's more tender.

Does the color ofbeef indicate quality?

White fat suggests that the animal was fed corn or other cerealgrain, at least during its final months. Yellow-tinged fat indicatesthat the steer was grass-fed. Consequently, a steak surrounded by apearly white layer of fat should be more tender-and expensive.

Is it easier to overcookpork today than 50 years ago?

Pork used to be rather fatty. Today's pigs are bred to be relativellean owing to public demand for lower-fat food. With less exteriorand internal fat, overcooking is less forgiving. Pork can easiltoughen and lose its succulence.

What is the needed cooking temperature to kill trichinosisin pork?

Cooking the meat to an internal temperature of at least 137°Fkill any trichinae present. (You can kill it by freezing the meat at atemperature below minus lOOF for several weeks, but freezing alters the meat's cellular structure, making it mushy when cooked-)

Intelligent safeguarding is not the same as overreacting, whichis what many cookbooks are doing when they recommend cooking pork to a temperature between 170° and ISS°F.lfyou followthose directions, your meat is bound to be less palatable and nutritious, and furthermore, prolonged cooking causes dryness,toughness, and excessshrinkage owing to moisture loss and coagulating proteins.

You can tell whether pork has been overcooked with the knifeand-fork test. If the meat does not cut easily,it's overcooked.

The other side of the coin is that you don't want to cook yourpork to just 137°F because the meat's flavor would not develop'

meats . . 65

For pork that is both rewarding and safe to eat, we recomcooking it to an internal temperature of 150°F (a 13°Fsafety

marginl.The center ofa pork roast will be slightly pink.See chapter 14 (p. 2SI) for more information on trichinosis.

en using a meat thermometer, whyshould 1test the thickestart of the meat and avoid letting the thermometer's point touch

boneorpocketoffatl

Since the center of the meat's thickest section is farthest away fromthe oven's heat source, it is the last part to cook. Even if the thermometer gives the desired temperature for a thinner part of themeat, the thickest segment may not be done.

Bone is a better conductor of heat than meat. If you take yourtemperature reading next to a bone in the center of the meat, thereading will be higher than it would be for center flesh farther

from the bone.Fat is not as good a heat conductor as meat. Placing the ther

mometer point in a pocket of fat, therefore, gives a lower readingthan it would for the adjacent flesh.

,~?wdo experienced cooks tell whether a meat is cooked simplyby

t9uching it?These cooks are testing for resiliency. Ai; the meat cooks, its fleshbecomes less flabby because it loses water and its muscle fiberscontract. The more a meat cooks, the firmer and more elastic it

becomes.The skill of accurately measuring doneness of meat by its

springiness cannot be taught in words. The best way to learn thetechnique is empirically, by testing the resiliency of the meat eachtime you use a thermometer. Eventually,your educated finger willrelegate the thermometer to the drawer.

'Are the minutes-per-pound charts for cookingmeat fallible?

Granted, the information garnered from such charts is better thanno information at all. Nonetheless, there are a host of variablesthat render the charts crude estimates at best.

i,I'II"II

i!1

II'I!I

the bacon oftoday tend to splatter more than that of

Generally, yes. In order to sterilize a ham so that it can be stored atroom temperature on a grocery shelf the processor must heat theham to a very high temperature. That intense heat negatively altersthe ham's flavor, aroma, texture, and nutritive value. Moreover,processors seldom reserve their best hams for their need-notrefrigerate products.

a canned ham that requires refrigeration better than one that

and limits their use with others by setting minimum periods between the day the animal last receives the hormones and the day itis slaughtered.

From a gourmet's point of view, hormone-infiltrated meat iscomparatively flabby and insipid.

W nar zrves a slice ofham an iridescent sheen?

The glistening, greenish, somewhat rainbowlike color that sometimes emanates from the cut surface of a ham slice is a sign of oxidation and not necessarily of spoilage. When exposed to oxygen(or light), some of the nitrate-modified iron content of the meatundergoes a chemical change that alters the ham's pigmentation.

In Grandpa's day, bacon was typically cured with dry salt-theslow, traditional way. In the interest of saving time and money, almost all the processors today cure their products in brine. Thisliquid infuses the bacon, which is the number-one cause of greasesplattering out of the pan onto the top of your erstwhile cleanrange.

meats . . 73

un_••• it best to fry baconwith medium heat rather than high?

splatter and curl are two answers. A more important reasonconcerns carcinogens. The hotter the heat, the more you convertthe nitrate curing agents into nitrites, which are substances suspected ofcausing cancer.

nique gives the meat surface and meat drippings added texture,flavor, and color-and, in some instances, seals in internaljuices.

72 • . the new kitchen science

Was USDAprime beefbetter a few decades ago?

On the average, yes. In the not too distant past, 4.5 percentcarcasses that were quality-inspected by the U.S. DepartmentAgriculture were awarded the prime grade. (USDA officialsfor ample marbling, white fat, bright, fresh flesh color, andfine flesh texture.) When the USDA lowered its grading standardsin 1976, that percentage jumped to 6.5- which means thatproximately one-third ofthe beefbeing sold today aswould have been stamped before 1976 with the nextclassification, USDA choice.

Even the USDA choice designation isn't what it used to be.category once encompassed 54 percent of the carcasses. Todayincludes 68 percent of them. The increase is due to the inclusionof beef that prior to 1976 would have been given the tmrd..levelgrade, USDAgooci

Why is the meat nearest the bone usually tastier?

In a given cut of meat, the meat closest to the bone has a distmctadvantage. It is in the best position to absorb the savory flavorsthe bone-the same flavors that help enrich stocks.

Is meat still safe to eat if I forget to cut off the government gradeinspection stamp?

Yes. The ink used is a harmless vegetable dye.

Why the controversyover using hormones to stimulate animalgrowth?

Although it is incontrovertible that sex hormones like cnetnyistilbestrol (DES) can accelerate the growth of livestock, manytritional authorities fear the effect of these natural or synthetichormones on humans who eat the meat. Consequently, the .'U'O.'"government forbids giving growth hormones to some animals


Do farmedfish grow faster than their wild equivalents?

Considerably so. Because of selective breeding and high-teching, some species that would normally take three years to reamature length in the wild will do it in less than one year on afarm. The cultivated fish - though just as long as the wild onewould have a blander taste and less firm texture.

Are there negative consequences when farmed fish escape intothe wild?

Environmentalists are concerned that genetically manipulated fisspecies may (and sometimes do) escape into the oceans, lakes, anstreams and breed with their wild counterparts. This woulthreaten the survival of the wild fish by modifying the genetimakeup of their offspring, making hatchlings less capable of surviving in the highly competitive natural habitat.

What causes a "fishy" odor?·

Bacteria are responsible. When bacteria attack a dead fish, thchemical trimethylamine is gradually released from the flesThese molecules, along with other substances created by the decomposition process, waft through the air, filling your nasal passages with odors reeking of ammonia. Sulfur, too, is generated bthe deteriorating flesh. A fresh, just-caught ocean fish does nhave the "fishy" odor. It smells like a fresh sea breeze.

Not to be confused with the fishy scent is the equally nauseatioil-and-kerosene odor that often emanates from fish that swambustling harbors.

Why are gills an early warning system for decay?

The gills are the respiratory organs located underneath the elike flaps behind the eye. When a fish is alive, blood is pumpethrough the gills and absorbs oxygen from the water. During thaabsorption process, the blood's hemoglobin undergoes a chemiprocess and turns bright red.

seafood • '81,

If the fish is properly stored after it dies, the oxygen in the airill.help keep the gills bright red for a few hours. Then overoxida

11. gradually changes the hemoglobin from bright red to pink tilownish red and finally to grayish brown.pills provide an excellent early warning system because they are

(lie perishable than the flesh of the fish and will develop an 11ft'(It before the flesh starts to acquire the telltale scent.

pad sign ifa raw fillet has yellowed along its edges?

ally such a fillet is over the hill. As it lies in storage, the filletdually loses acidity, and unavoidably, the normally white flaIi~pigment in the fish flesh picks up a yellowish tint. Oxidation(lplays a role in the yellowing process.

(I\l:e the othermajor freshness tests for a whole fish?

sshould be bright, clear, and bulging and look alive rather than,cloudy, or sunken. Scales, if they exist, should be securely ated, If scaled, the skin should be shining (not slimy), and reo

ent when pressed with the tip of the finger. If the fish is gutteditshould be if dead for more than an hour), the stomach cavityuld be free of excess residue. Any exposed flesh should be firmIustrous, not flabby or dull, and should cling tenaciously topone. When the fish is held horizontally by head and tail, the

dsection should not sag appreciably.

oes seafood in fish stores sometimes look slimy?

issheenis usually caused by bacterial decay, but not always. Themical additive tripolyphosphate (nicknamed "tripoly' in thede) is sometimes the culprit, especially when it's used exces

y by overzealous fishermen and seafood processors.Jhe method is simple: The seafood is soaked for several hoursa. tripoly solution. The resulting chemical reaction retards theterloss that occurs naturally in protein tissue when a life form*.Protein tissue loses water during the postdeath stage becau~e

molecular structure contracts, decreasing its water retention

seafood • . 85

Try This Fish-SteakExperiment

Buya center-cut and a toil-cut fish steak

ofequal thickness and cutfrom thesame fish. Sauteor broil both andcross-taste. Which steaktastesbetterand has a moredesirabletexture?

y do freshwater fishes have more of those small, annoyingnes than marine fishes do?

Salt water contains a greater concentration of minerals (particulady salt) than does fresh water and therefore has a higher specificdensity. Thus, a fish has greater buoyancy in salt water. This addedbuoyancy allows a saltwater fish to have a heavier bone structure.When some of the oceangoing fishes made the switch to a freshwater home eons ago, they evolved a lighter, thinner, more delicate bone structure to compensate for the diminished buoyancy.All well and good for a fish,but what about the millionsof diners who dread chokingon tiny, spiny bones?

y do river fishes generally taste better than lake fishes?

Exercise builds flavor into flesh. Since a river fish must swimagainst the current just to remain stationary, it obviously needs toexpend more energy than a typical lake fish.

Not all river fishes oscillate their tails with equal vigor andintensity. An angler should expect less flavor in a fish that lazilywends its way along the sillcy bottom of a river than, say,in a troutthat maneuvers its course through a cascading, cold mountainbrook.

is the center cut ofa fishperior to the tail cut?

The meat from the center cutusually has a higher fat content and therefore a richer flavor. Though the tail's flesh has amore intense flavor because of the extra work the tail must do topropel the fish through the water, the gain in quantity of flavordoes not begin to match the loss in flavor quality. In terms of texture, the center cut is usually just right- not too flabby, nor toofirm. The tail section is tough by comparison.

84 • • the new kitchen science

Is the difference between a fat and lean fish important to rondieters as well?

Yes. Generally, the more fatty the fish, the more flavorful theVitamins and other nutrients in the flesh also tend to increasestep with a fish's fat content.

The darker the flesh color of a particular spedes (or a giveanatomical area of a particular fish), the higher the fat content islikely to be. If you want your fish flesh to be as lean as possible,white fishes are usually your best bet.

Fat content usually decreases in relation to the depth of a fish'sliving environment. At a given latitude, bottom-dwelling fisheslike sole and cod are usually leaner than those, such as tuna andherring, that dwell near the surface. And any given fish will beleaner after it has spawned or experienced a food shortage.

Why do fishes from cooler waters generally taste better?

As we mentioned in the' preceding Q&A's, there is often a discernible correlation between fat content and richness of flavor.Cooler-water fishes tend to have a higher fat content because,among other factors, their eco-environment contains a greaterabundance of plankton at the bottom of the food chain.

Moreover, because Temperate Zone waters are colder and morturbulent than tropical ones, plankton and mineral particles armore likely to remain suspended in the water, creating a richerfood source for non-bottom-dwelling fishes. (Note: Tropical waters are clearer than Temperate Zone waters simply hecause theyhave less suspended matter.)

A good Illustration of the gastronomic effectof water temperature is the comparison between the flavorful fishes hooked or netted in Georges Bank off the New England coast and the speciescaught in the Caribbean Sea. With rare exception (for example,the pompano), semitropical-and especially tropical- fishes arerelatively bland. Shellfish from those sun-drenched shores, how.ever,are usually gustatory delights.

90' • • the new kitchen science seafood . . 91

y doesn't fish have to be cooked to tenderize it?

Unlike red animal meat, the flesh of fish has meager connectivetissue, the muscle component that can make raw red meat relatively tough and dry. The small amount of connective tissue in theflesh ofa fish is more easily gelatinized by moist heat than the kindfound in the flesh oflandlubbers. Excess cooking (and it doesn'ttake much) is inappropriate because it toughens the muscle fibersunnecessarily without tendering any meaningful payment in return.

the middle of the week. This increases the chances that the chefdoesn't replenish his inventory on a daily basis. Our recommendation is to enjoy sushi only at a quality Japanese restaurant that is

day and has a conscientious sushi chefwith impeccablestandards. Youwill pay more, but it is~orth it.

enwhy is fish cooked?

Cooking helps destroy any existing pathogenic microorganismsand-e-lf not excessively done-develops and distributes flavorand coagulates the protein muscle fibers, a chemical process thatgives the flesh pleasing firmness and opaque color. This coagulation can be accomplished with nonheat methods, too. Tahitiansand Peruvians, for example, have for centuries marinated freshlycaught and dressed fish in lemon or lime juice, calling their cookedspecialties, respectively, l'ora and ceviche. French Polynesians calltheir version of the first dish poisson cru (literally"raw fish").

pes it make a difference to a cookwhether the flesh ofa fish isorlean?

yes, very much so. A fat-fleshed fish is better suited for grilling orroasting because of the extra oil it contains. A lean-fleshed fish isbest cooked in an oil or liquid; ifgrilled or roasted, it tends to dryout unless the flesh is frequently basted.

Few realizethat it's risto eat fishcaughtaff

one ofthemostpopulfishing spolia bridge

fish caught off one of the most popular fishin& spots~a bridge.Auto exhaust fumes and the rubbish people dump in the middleof the night can pollute the waters near a bridge.

Fish caught in coastal waters (particularly if near an urban tenter) are exposed to far more contaminants than deep-water denizens. This is why the flesh of a deep-water, 300-pound tuna is lesslikely to be contaminated than that of a shore-hugging, 8-ounceporgy.

A large fish (and the people who eat it) maynot be as fortunate if it lives near an industrialmetropolis. Its flesh will likely have a higher concentration of toxic mercury than that of smallerfishes. Here's why. Bottom-dwelling shellfish ingest mercury waste that settles to the oceanfloor. The mercury in these crustaceans is transferred to the fishes that devour them, then transferred in turn to the fishes that eat them. Eventually, some of the mercury ~eaches the top of thefood chain-fishes such as tuna, sharks, and swordfish. Theselarge fishes live longer than smaller fishes and thus eat more fleshin a lifetime. Because mercury is difficult to expel from the body, a.large fish living in coastal waters may become a repository ofunsafe quantity of mercury before it's caught.

Is it safe to eat sushi?

The flesh of healthy fish living in unpolluted ocean water is free 0

pathogenic bacterial contamination. If such flesh comes fromnonpoisonous fish, is properly stored for not more than half a daor so, and is correctly cleaned and prepared, eating sushi poses nmore threat to your health than consuming a wholesome rawter or clam gathered from uncontaminated waters.

Unfortunately, many Japanese sushi bars in America (andin Japan) serve less than perfectly fresh fish, and the seafood isalways hygienically handled. And to make matters worse, manythose sushi bars do not teem with customers during peak hours


89.65.13.60.7

99.0100.0

87.35.03.50.7

96.5100.0

3.5%

dairy products . . 107

Contents of Whole Milk

NONFAT COMPONENTS

WaterCarbohydratesProteinMinerals, etc.Subtotal

Total

NONFAT COMPONENTS

WaterCarbohydratesProteinMinerals, etc.Subtotal

Total

Fat

Contents of 99 Percent Fat-Free Skim Milk

Fat 1.0%

low-fatmilkhave the same nutrients as whole milk?

W'W-IaJ milk has all the nutrients that whole milk contains exceptthe fat removed by the dairy. Although low-fat milk is a smart

for those on low-fat diets, it lacks the richer, fuller-bodiedand mouth-feel ofwhole milk.

Fizuresfor a typical 99 percent fat-freeskim milk or buttermilk arefollows:

["""I,.... sweet milk become sour milk?

5 percent of fresh milk's content is lactose, a milk-sugar!'?llrbohy(lra:te that gives the liquid a slight but noticeable .sweet

the milk ages, certain bacteria devour some of the lactose,r1">,w..rtine it into lactic acid. Result: The milk sours.

The oxolic ad

in chocolate'

hibits the dig

tive system'}

ability to abs

the calcium'

chocolate

Though the chocolate flavoring is often an enticement, it is ullsound from a nutritionai standpoint. The oxalic acid in chocolate inhibits the digestive system's ability toabsorb the calcium in chocolate milk. Theoxalic acid chemically reacts with the calcium, producing a new compound, calciumoxalate. The intestines cannot absorb thiscalcium oxalate because it is insoluble. Thisloss of the essential mineral calcium is nutritionally detrimental, especially for growingchildren.

needs than a human baby-its growth rate is about twice that aits human counterpart. Because its casein content is higher, cow'milk is harder to digest than human milk. If the milk weren'stretched with water and the baby's intake of the milk (and its casein) thereby reduced, it would put a strain on the baby's delicatdigestive system.

Sugar is added to the cow's milk to make the infant's formultaste more like human milk, which is naturally sweeter. Speakinof sugar, a parent should not let a baby get into the habit of fallinasleep with a milk bottle. This beverage (as well as sugary fruitjuices) is laden with bacteria that can cause tooth decay. If a parefeels the child needs a nightcap, the bottle crutch should canplain water.

What is the difference between 96.5 percent fat -free milk andwhole milk?

There is none. The phrase "99 percent fat-free" on skim milktainers has misled many a shopper into thinking that wholeis 0 percent fat-free. Most of the whole milk sold in theStates is 96 to 97 percent fat-free. Here is a breakdown ofwhole milk from a cow, stated in percentages.

Is adding chocolate to milk a good way to'entice children to drinkmilk?

y is standard stickbutter better for cooking than whippedtter?

Whipped butter is merely standard butter inflated with air. A disadvantage of whipped butter is that almost all recipes are basedupon standard butter measurements. You must increase the volume of butter called for by one-third if you use whipped butter,because that product is approximately 25 percent air. The sitoation becomes even more complicated ifyou use tob butter, whichcannot be measured as easilyand exactly as units ofstick butter.

Whipped butter's advantages lie beyond the stove. Because it is

is saltedbutter a bane to cooks?

The salt content of salted butter can vary from brand to brand,and from region to region. One batch ofbutter may have I lh percent salt and another twice as much.

Even if you stick with one brand and know its exact salt content, it is a headache to calculate the amount of salt you mustsubtract from a recipe that calls for a given quantity of sweet (unsalted) butter. Since the recipes from virtually all serious cookbooks are based on the use of sweet butter, people who cook withsalted butter create an extra complication for themselves (unless,ofcourse, one's religious code dictates its use).

particularly rich in orange-yellow carotene. When winter comes,so does a paler butter.

Because the average American consumer wants consistency,butter manufacturers try to give their products year-round uniformity by using dyes such as annatto seed extract or carotene. Abutter made with winter or Holstein cow milk, for instance, cantherefore be made just as rich in color as one from springtime orJerseycow milk.

Color is a quality indicator, however, when it comes to uniformity in a particular sample. White streaks or multiple shadesof yellow indicate a defect in the cream ingredient, productionprocess, or storage.

dairy praduds . . 113

Salted Butter

810/01621

Sweet Butter

810/018o1

FatMoistureSaltOther

What is the composition ofbutter?

Despite the efforts of the American dairy industry to standardizbutter, its composition can differ from batch to batcb becausefactors such as the cow's breed and feed, season, local legislationand dairy policy. If we take an across-the-board average, theposition by weight percentages is as follows:

Salt is used to extend storage life. "Other" comprises-inscending order ofweight - protein (mainly casein), carbohydra(mainly the milk sugar lactose), and minerals other than salt. Buter's calorie count is approximately 100per tablespoon.

How is soy milk made?

Pure soy milk is produced by straining the liquid of mashedbeans cooked in water. Often soy milk is doctored with a sweeteing agent, infused with flavoring agents like almond, and fortifiewith calcium, other minerals, and vitamins. Soy milk is a minomer- it does not contain any milk and does not even vaguetaste like genuine milk. Soy milk is popular with people who sufffrom lactose intolerance (soy milk has no lactose) or milk aller(it has no casein). Vegans-and other vegetarians who absfrom dairy products - are also soy milk drinkers.

Is butter color a reliable indicator of quality?

Natural butter can vary from the palest of yellowsto a deep yellodepending on the cow's breed and feed. Certain breeds, suchthose from the Channel Islands (Jersey and Guernsey), produdeeper yellowbutters. All cowsproduce their deepest-colored b1lter in the springtime and early summer, when the grass they eat



airier, whipped butter spreads more readily on bread and meltsmore quickly when used as a topping for warm foods like waffles.

How do I keep butter from scorching?

Butter begins to scorch when the heat changes the character of theprotein. One way to help prevent or minimize this problem is touse clarified butter, from which the protein has been removed. Mother is to use a 50-50 mixture of butter and vegetable oil, whihas a higher smoke point than pure butter. Whether you emplothe clarified butter or the 50-50 method, do not expect yocooked foods to pick up the full,rich flavor ofwhole butter.

Whydoes butter go rancid?

Oxygen is the chief culprit. Off-tasting and -smelling compoundare formed when oxygen comes in contact with the unsaturatefats in butter. You can slow down this chemical reaction by lowering the temperature (frozen butter lasts longer than refrigeratebutter, which lasts longer than room-temperature butter) and bytightly wrapping the butter (to minimize surface exposure to air)!Another method for fighting rancidity is to change the butter intclarified butter (see p. 117).

Just because a butter goes rancid doesn't necessarily mean it hbecome unwholesome. In fact, butter's vulnerability to bacterispoilage is lower than most people think because butter is a waterin-oil emulsion. Consequently, each water particle is sealed in anenvelope of fat. This means that the bacteria dispersed in the waterand in the butter cannot spread freely.

What are the advantages ofclarified butter?

Clarified butter is superior to regular butter in two salient wayYou can fry with it at a higher temperature, and you can store.'longer. These benefits are not won without a sacrifice: Clarifiebutter lacks most of the characteristic buttery flavor that main!comes from one of the removed substances, the protein casein.

You can fry with clarified butter at a higher temperature be

dairy products . • 115

cause you raise its smoke point from about 250° to 350°F whenyou remove the butter's protein, which is the component thatscorches first.

Clarified butter has a longer storage life because it is primarilythe protein in the butter that makes butter vulnerable to spoilage.If it is superclarified, as is the fabled ghee of India, you can storeclarified butter at room temperature for months without ill efects,

.atare the principles ofclarifyingbutter?

To clarify butter, you must separate the fat from the nonfat ingredients. The more completely you remove the nonfats, the moresuitable your clarified butter will be for frying and storing. Manyotherwise intelligently written cookbooks detail unnecessarilyburdensome procedures for doing this. Our method is less complicated. Moreover, it eliminates the risk of scorching even onemolecule ofbutter, a threat posed by the frequently recommendedtechnique ofmelting it in a pan over a flame.

When butter melts, its emulsion breaks down. The butter thenbegins to separate into three distinct strata: a thin, whitish upper

er of foam; a thick, yellow middle layer of fat (your clarifiedutter); and a medium-thin, whitish bottom layer ofwater infused

'\\'ithcarbohydrates and, especially,proteins, casein being the mostimportant,

The protein-carbohydrate water solution that makes up thebottom layer contains no fat because the fat, having a lower specific density than the bottom layer, has followed the immutablelaw ofnature by rising. (Or you could saywith equal logic that theprotein-carbohydrate water solution has sunk.)

The foamy upper layer is often erroneously referred to as anitnpurity-based scum. This layer is principally made up of water,proteins, and carbohydrates and is thus similar to the bottomlayer. It is prevented from dropping through the fat layer becausethe trapped air in the frothy structure literally keeps these particular nonfats floating on top of the fat layer. By the time the bubbles

119dairy praduds

can I store a hard cheese longer than a soft cheese?

Ahard cheese has a lower water content. Since water is a mediumconducive to the growth of spoilage-causing bacteria and mold, ahard cheese like Cheddar (about 37 percent water content) willlast much longer than cottage cheese (between 70 and 80 percentwater content).

Once any cheese is opened, however,you want it to retain moisture for the sake of texture. To minimize moisture loss, keep ittightly wrapped in your refrigerator. This shield also helps keepthe cheese and its storage mates from exchanging odors.

Taking a cheese back and forth from refrigerator to diningroom table robs it of moisture and hastens decay. If you have apiece of cheese too large to eat all at once, cut off and bring toroom temperature only what you plan to eat and leave the remainder tightly wrapped in the refrigerator.

does a cheese sometimes refuse to melt in a sauce?

Chances are the cook heated the cheese at too high a temperatureor for too long. Such treatment separates the protein from the fatand makes it tough, rubbery, and stringy. A cook who continues toheat the sauce in the hope of melting the unsightly protein lumpsis pursuing an impossible dream. Once the damage has been done,further cooking only makes matters worse.

A cook's two primary goals therefore are to minimize the levelof heat and the length bf time that will be necessary to melt a particular cheese. The first goal is reached by keeping the heat sourceat a low setting and, for even heat distribution, using a thick-bottomed pan or double boiler. To achieve the second goal, bring thecheese to room temperature and cut it into small pieces. If thecheese is dry-as, for instance, a Parmesan- it should be finelygrated. Add the cheese just before you have finished cooking thesauce, stirring all the time.

Different types of cheeses have different melting characteristics. Processed cheeses like American cheese melt more quicklyand easily than most natural cheeses because they have low melt-


Is it safe to eat a cheese with mold?

There are two types of cheese molds: desirable and harmful.sirable molds create the crust on brie, camembert, and other Socheeses- and the veinlike mold inside Roquefort and other hicheeses. Without these beneficial molds, the cheeses wonld nproperly ripen or taste as good.

Harmful molds are virtually everywhere and attack both soand hard cheeses. Their high toxicity level can make you sick,worse. They normally arrive airborne, landing uninvited on tlicheese at the factory, on the truck, at the store, or in your homThese harmful molds quickly multiply on the cheese surface abore into the cheese with their threadlike filaments called hyphae

A contaminating mold's hyphae penetrate considerably fastin a soft than a hard cheese, owing to less physical resistance amore moisture, which aids the mold's growth. Hyphae are notways easy to spot, so it is wise to discard a soft cheese that shoany sign ofcontamination.

You can usually save part of a hard cheese if the mold covejust a small surface area and there is no evidence of hyphae pentration. Cut away the afflicted area to a distance of 1 inch in allrections (including down) from the mold. Do not let theblade touch the tainted area.

If you enjoy yogurt (as we do), eat it plain or add your afresh fruit. Unless you plan to store your yogurt mixture for adays, there is no need to add sugar to preserve the fruit.

Should I buya cheese that has an ammonia scent?

Many a cheesemonger has convinced uninformed customersthe ammonia scent ofa surface-ripened cheese such as camembeindicates that it has reached its peak of maturity and that Frengourmets love eating their cheese in this condition. Not so. Onyou can smell more than a trace of ammonia, the cheese is athe hill because it is sensory confirmation that certain enzymesattacking countless amino acids, a process that spoils the


will not change their form or the ice cream's texture, unless thecream is stored for a prolonged period or at a temperaturebelowO°F.

Shonld I scoop ice cream with a circnlar, horizontal motion, asmany ice cream parlors do?

Not if you want to retard melting, which is usually a must whserving the product at home meals. Many ice cream parlors usthe circular motion because slow melting is not their top prioriProfits are. An employee would get fewer servings per tub if hpressed the scoop downward into the ice cream than ifhe draggethe scoop in an arc on the ice cream's surface. With the firmethod, the ice cream compacts, creating a denser, slower-mel .scoop. With the second method, the ice cream curls, creatingspaces. The customer ends up with a faster melting, poorer-valuiproduct.

995

\v can I tell whether an unopened egg is raw or cooked?

pin the egg on its side on a flat surface. If your egg rotatesmoothly, with effortless grace, it is hard-cooked. If your egg wob

pies noticeably, it is uncooked. The wobbling occurs because centrifugal force continuously changes the raw yolk's position insidetile egg and so keeps altering the egg's center ofgravity.

I tell whether a raw egg is fresh without breaking it?

Xes. Place the suspect egg in at least several inches of water in aowl or pot. If your egg sinks and lies on its side, you have a freshgg. If it sinks but stands partially or fully erect on its tapered end,

your egg is over the hill, though technically still edible. If it floats,you are looking at a rotten egg, more suitable for a garbage heapthan a stomach. An egg acquires buoyancy as it ages because, whileits yolk and albumen (egg white) are gradually losing moisture totile outside world through the porous shell, the size of its airpocket is increasing.

do eggs fare in the cholesterol department!

;'l'1le American Heart Association's dietary guidelines once recommended eating a maximum of three eggs a week. New research on

123

1 in 10,000

eggs • . 125

The chanceafan eggcontainingsalmonella israre-abaut

fresher eggs are also superior when you use the yolk to leaven,thicken, or emulsify a preparation. Moreover, the recently laid eggis easier to separate because as an egg ages, the membrane of itsyolk weakens. Finally, an egg fresh from the coop has more flavorand nutritional value. ,

For the record, the egg nestled in a box in the supermarket display case is usually three to ten days old, though two- or three

eek-old eggs are not rare in municipalities that do not requirepen dating. Some firms extend the storage life of their eggs to six

months by coating the shells with a light mineral oil that helpskeep harmful bacteria out and beneficial moisture and carbondioxide in. Another method ofgiving whole eggs superlongevity isstoring them in carbon dioxide chambers.

auld raw eggs be frozen in their shells?

No. Always shell the eggs first, because freezing expands the contents of the eggs more than the shells' capacity. Result: cracked~ggs. You can freeze the yolks and whites separately or together.The relatively high fat content (32 percent) of yolks gives them ashorter freezer life than whites. Since freezing deteriorates textureand flavor, freeze eggs only when necessary.

at are the chances ofbeing exposed to salmonella from a

Wegg?

Salmonella is a food-borne bacterium that can make people seri()J1sly sick with intestinal flu-like symptoms. Thanks to improvedfarming and storage procedures, the chance of an egg containingsalmonella is rare-about 1 in 10,000.

Those odds are trifling compared to the oddsofa store-bought chicken being infected with salmonella. (Research estimates range from 1 in~. to 1 in 20.) What this tells us is that peopleshould be hundreds of times more. concernedabout eating undercooked chicken than underooked eggs.


Are fertilized eggs more nutritious than unfertilized eggs?

Many health food store~ make this claim. However, the chickeembryo in a fertilized egg is so small that the amount of extratritional value it offers is inconsequential.

Are brown eggs more nutritious and flavorful than white eggs?

No. Though some chickens that lay brown eggs produce more n«tritious and flavorful eggs than the breeds that lay white eggs, tliopposite is true just as often. Therefore, shell color is not an indicator of quality.

Eggshell color marketplace preference is regional: In Boston th.brown egg is more popular, whereas in most other areas of 0

country the white is the top choice.

Why do some egg yolks have blood spots?

A yolk membrane can pick up blood spots as it travels downhen's reproductive tract before the surrounding albumen (ewhite) and shell have been formed. If the tract is bleeding, somethe blood can attach itself to the yolk. The blood spots are harless blemishes and, contrary to some food books, do not indicfertilization.

eggs has changed that rule. The AHA guidelines now permit aegg a day. An egg yolk contains 1'12 grams of cholesterol-raisinsaturated fat. This is not a high number, especially when you cosider that a yolk is packed with many essential nutrients and honly 75 calories.

Which is better, a week-old egg or one fresh from the coop?

It depends. A week-old egg is preferable for preparing a harcooked egg because the shell is easier to peel.

On the other hand, as an egg gets older, its yolk protein molcules gradually lose their binding abilities. This means that fresheggs are the first choice when frying or poaching becausehave a thicker egg white and firmer yolk, qualities that increthe eventual compactness and attractiveness of the cooked

eggs . . 127

hat temperature should egg whites be whipped?

Although egg whites separate from yolks better at refrigeratortemperature (see previous Q&A), they whip to their maximumvolume at room temperature. One reason is that the surface tension of the albumen is lower at room than at refrigerator temperature, Thus, small air pockets can be more easily incorporated intothe albumen to form a foam.

A foam is a superstructure ofbubbles. Each bubble is made upof a pocket of gas trapped inside a spherical film of liquid. Typi

y, the gas is air (as is the case with soap bubbles and beaten eggor carbon dioxide (think ofa beer head). The liquid cannot

pure water because its surface tension is so great that it's diffi-

are refrigerated eggs easier to separate than roomperature ones?

The viscosity of the egg white (albumen) and the surface tensionof the yolk membrane are noticeably greater at refrigerator temerature than at room temperature. This means that the albumen. more readily slide away from the yolk-and that the yolkembrane will be less likely to rupture during the separation

rocess when the cook moves the egg back and forth between thealves of the eggshell.

reason the separation between the yolk and air pocket isin the egg B pocket is because the air pocket arches upward (as

oes any air bubble rising through a liquid), whereas the pocketi# eggA is flatter because it is already above the liquid's surface.

The second reason is more complicated, The egg yolk is lighteran the albumen and will rise to its surface unless restrained,hich nature does with chalazas.. These are the two cords attached

11 either side of the yolk designed to keep the yolk anchored inthe center of the egg. The cord connecting the yolk to the smallerend is tauter than the cord tethering the yolk to the larger end of

egg. Consequently, the yolk does not float up as high when theis stored small end down.

8A

Whyshonld eggs be stored upright?

"Upright;' in egg-storing terminology, means with the larger enup (tapered end down), as shown by egg A in the illustratioabove.

Upright storage helps retard spoilage because it maximizes titdistance between the yolk and the egg's natural air pocket. Tgaseous space is potentially the egg's most prolific breeding enronment for airborne pathogenic bacteria, and the yolk is morperishable than the albumen (egg white). It stands to reason therefore that you must keep the yolk as far away as possible fromair pocket.


Whywere manyolder refrigerator models designed with thestorage compartment on the swinging door?

Accessibility, rather than storage life, is the prime reason foregg compartment's traditional location. The door is one of tleast sensible locations because the eggs are jarred each time yoopen and shut the door. Moreover, the eggs are repeatedly exposeto temperatures well above the ideal. That perfect temperature, bthe way, is about 30oP, just above an egg's 29°P freezing point.

Whether or not you have such a refrigerator, keep eggs in theioriginal carton (if it's clean) at the rear of the coldest shelf. Ndonly does this technique minimize jarring and temperature fluetuation, it saves you the transferring chore-and helps shield eggfrom refrigerator odors.

eggs . . 133

Try This ScrombledEgg Experiment

In bowl A, beat two eggs with 2 teospoons of cream (or milk or water). Inbowl B, beat two eggs without addingthe liquid. Cook each botch separately.Which method produces lighter,Ruffierscrambled eggs?

naturally coats the egg yolk membrane. You don't notice it at thebeginning of the cooking process because at that stage it is trans

arent.

Ydo I add a liquld to scrambled eggs?

your cooked scrambled eggs will be fluffier and more tender ifyou beat I or 2 teaspoons of water per egg into the raw eggs.Thisliquid steams as your egg mixture cooks, giving the scrampled eggsa lighter texture. Theeggs will also be moister because the cooked protein molcules can bind with more

water molecules than can uncooked ones.

Milk produces the same efeet as water and has the extra~dvantage of enriching yourpreparation. For even betterresults, use cream.

ydoes the portion ofthe egg whit~ that lies nearest the egg yolkmore slowly than the outer portion?

An obvious reason is that it is thicker. Another one is that it doesn'tcome in direct contact with the pan- the portion ofthe eggwhite

at lies nearest the eggyolk sits on top of the second type of albuI)len, the One that constitutes the entire bottom layer of the cooking egg.A third reason is less known. The inner albumen layer cogulates at a temperature about SOF higher than does the second

type ofalbumen.

If you wanI

perfect frill

egg, we a

vise cooki

as slowly

possible a

low heat

precipitates the setting of the egg whites before they have hadchance to spread too far in the simmering water. Vinegar alsblanches the eggwhites, enhancing their snowy luster. These benefits are overshadowed, however, when the cook uses other thanquality vinegar or pours the vinegar into the pan with a heahand, a bad habit common among short-orderchefs. A proper ratio is about I teaspoon ofvinegar (or 2 teaspoons of lemon juice) per quartofwater.

Salt also helps speed the coagulation process,but like vinegar, you must use a sparing amountlest you overpower the egg's flavor. A pinch ortwo of salt per quart of water should suffice.


What makes a fried egg rubbery!

Frying an egg at too high a temperature or for too long causesprotein in egg whites to. coagulate excessively and lose internmoisture. If you want a perfect fried egg, we advise cooking itslowly as possible over low heat-and removing it from theas soon as it is done. As a bonus, your eggwill absorb less fat.

Technically, it is impossible to fry an egg in the classicsensesimultaneously have a perfectly cooked egg white and a firm yoIf you cook the yolk to its just-right coagulation temperatur(about IS6°F), you will overcook the egg white (which begins set.ting at about 14S0F).

People who do not like runny yolks should tum the eggs "oveeasy" rather than wait for the yolks to firm as they cook "sunnside up." Or you could braise the eggs by covering the pan withlid - the trapped steam hastens the cooking of the yolk tops.sure to cook over very low heat and keep the lid closed (no peeking) to prevent steam from escaping.

The hue of a "sunny-side up" yolk is a bright orange-yelloHowever, a thin milky-white layer appears on the top of the yolk'you use any of the three egg-cooking methods mentioned in tprevious paragraph. What you see is a thin layer of albumen


Are there edible plants that humans do not eat?

We eat only a tiny fraction of the estimated tens of thousandsedible plants on earth. Wheat, rice, and corn account for overpercent of the volume humans consume.

Why do most raw, unprocessed fruits and vegetables tend todeteriorate so quickly?

Attack by microorganisms is one obvious answer. Deterioratioalso occurs because of enzymatic action within the fruit or veetable. In addition, the decomposition process generates hwhich accelerates the rate of microbial and enzymatic damaand moisture loss withers the food.

Why are produce items like apples and cucumbers sometimescoated with wax? .

The food industry does it for its own sake, not yours. A coatingwax helps seal in moisture and therefore extends storage life,well as minimizing costly weight loss. It also gives the fruit or veetable a sheen, which in the eyes of some customers isa signquality. Informed shoppers, however, know that it is an impossichore to wash off all the wax. Even if food industry spokespersoare correct in their claim that the wax is safe to eat, it does gifood an off-flavor. It also thwarts your efforts to scrub off pe .cides that may have been sprayed on the fruit before it was wThe list of fruits and vegetables that are falling victim to the Voltreatment is lengthy, and growing: Apples, cucumbers, orangelemons, grapefruit, bell peppers, pears, cantaloupes, plums,yams are among the casualties.

How important is cellulose content in determining howlong tocook a vegetable?

Cellulose, a complex carbohydrate, is the chief constituentcell walls of vegetables (and fruits). The higher its proportionithe cells, the firmer the raw vegetable will likely be. To tende .the cellulose, and therefore the vegetable, the cook generallycombination ofheat and moisture.

fruits and vegetables . . 137

Some foods present a special problem. Consider broccoli andasparagus. The stems have a higher cellulose content than the tipsand will therefore still be undercooked by the time the tops aretender unless remedial action is taken. Suitable solutions includecooking the stems and tips separately or cooking them togetherbut giving the stems a head start. You can also shorten the cookingtime required for the stems by paring them (a siguificant percentage ofthe cellulose resides on or near the surface) or by cutting thestem into smaller pieces.

The difference in cellulose content is the principal reason brownrice has to be cooked approximately twice as long as white rice tomake it palatable and digestible. Unlike white rice, brown rice stillretains the outer bran layer, which has a high cellulose content.(The endosperm- the white inside part of the cereal grain - hasfar less cellulose.)

Apples like Red or Golden Delicious are unsuitable for cookingbecause, lacking sufficient cellulose, they become mushy and losetheir shape. In addition, they do not contain enough acid to balance the sugar often added by the cook. York Imperial, RomeBeauty, and crab apples are among those that cook well.

!!'Wnecessary is moisture for the softeningofcellulose?

The need for moisture can be demonstrated by trying to cook abeet with dry heat (baking, for instance) rather than with moistheat (simmering, for example). The beet does not contain enoughmoisture to soften its high cellulose content. Near the other end ofthe cellulose-and-moisture spectrum is a tomato, which has so little cellulose and so much moisture that its structure will collapse ifoverbaked.

at other roles do heat and moisture play in tenderizingetables?

.!feat destroys the osmotic capability of the cells and therefore diminishes the food's structural firmness. Heat in conjunction withmoisture also tenderizes by dissolving some of the pectic substances that help glue the individual cell walls tightly together.

Try This Acid-DiscolorationExperiment

fruits and vegetables • • 139

,iBuy a standard-size package of frozenpeas. Defrostit. Flavor the peas with1/2teaspoon of vinegor (or 1 teaspoon

of lemon juice). Dividethe peas intotwo equal-portioned batches. Callthem batch A and batch B.Cook batchA in a lidded saucepan (to trap theacid in the pan). Cook batch Bin anuncovered saucepan. Which botchhas a brighter, more appealing hue?

steps encourages the leaching out of unwanted flavor and odorcompounds into the water.

Interestingly, cooking onions and garlic for prolonged periods(just as long as you don't burn them) has an opposite effect. Theybecome mild-flavored.

at causes a green vegetable to turn muddygreen when cooked?

i\.cid, coupled with heat, is the villain. In combination, they denature chlorophyll, the chemical compound responsible for givinggreen fruits and vegetables (aswell as the leaves of the forest)their characteristic pigmentation.

By cooking without a lid,you minimize the discoloration caused by acid (which isgenerally volatile and dissipates into the air).

tbetter to boil a vegetable covered or uncovered?

Whether or not you use a cover depends on your priorities. Whentou cover a pot, you reduce the number ofnutrients that dissipateinto the air. A covered pot also cooks at a higher temperature thanalidless one, so the vegetable cooks more quickly, and nutrients~ave less time to leach out of the food. Without a lid, the vegetables better retain their vivid green (see the next Q&A).

Quid raw green saladvegeIlles be added to salad justfore serving time?

A strong vinegar-based saladdressing can tum green salad vegetables, like green peppers, amuddy green in a matter of a half-hour or so, for the same reasonmentioned in the previous Q&A. Solution: Add the acidulousdressing just before serving.

Does prolonged cooking bring out the flavor ofeither cabbageor turnips?

Too many homes reek unnecessarily with objectionable odors because the cook has been misled by a recipe or by grandmotherladvice into believing vegetables like cabbage and turnips shoulbe cooked for a long time. For your nose's sake, and for the sake 0

texture, don't overcook such vegetables.Another way to avoid the disagreeable qualities sometimes as.

sociated with cabbages and turnips is to buy them young anfresh. As these vegetables mature or spend time in storage, theiflavor and odor strengthen. If you are forced to use some that aovermature or have been stored for a while, you can still minithe potent taste and smell. Cut them into small pieces andthem in an uncovered pot with plenty ofwater. Each ofthese

Is it advisable to cook vegetables in as little water as possible?

Water can leach water-soluble vitamins (B and C) out of food. Thless water you use, the fewer vitamins you lose. Many leafy vegetables, including spinach, need no water because the moisture thaclings to the leaves after you have washed them is ample for illfirst minute of cooking. As the leaves cook, they contributenough water of their own for the pot. However, cooking in a generous pot ofwater is called for when you want to reduce the stroIlflavors ofsome vegetables.

What other factors determine the cooking time ofvegetables?

Dozens of other variables enter the equation, including individupreference, piece size, cooking method, degree ofheat, and atmospheric pressure-factors that we discuss elsewhere in this book.


Does acid affect the cooking time ofvegetables?

Acid slows down the cooking process, which helps explain whbeans cooked in a casserole made with tomatoes require 10 to 2percent more cooking time than a nonacidic baked bean dish. Alikali has the opposite effect ofacid: It shortens cooking time.


Why do green vegetables cooked with baking soda have a brightercolor?

Baking soda helps maintain the vivid green because it is an alk .and therefore neutralizes the discoloring acid in the vegetablecooking water. However, we strongly advise against nsing bakinsoda for this purpose. It destroys vitamins (particularly vitaminand thiamin) and, by softening the hemicelluloses of the vegetable's cell walls, gives the food a mushy texture.

What causes red cabbage to turn bluish purple when cooked?

The principal pigment in red cabbage is the chemical compounanthocyanin. Acid turns it red, and alkali a bluish purple. The cabage is red to begin with because of its high acid content. When}is cooked for more than a brief period;much of its acid escapinto the air with the steam. When enough of the acid has dissipated, the alkali in the pot becomes predominant and turns thcabbage bluish purple. The harder the water, the greater its alklllinity, and therefore the more the cabbage discolors.

What gives carrots and other yellow-orange fruits and vegetablestheir color?

Carotene. Besides adding a colorful excitement to foods,chemical compound- unlike the other major fruit and vegetabpigments-is a valuable nutrient. Because it is a provitamin A,"can be converted by your body into vitamin A.

If you've ever seen a vegetarian with a yellow skin tone, he mbe suffering from hypercarotenum. It is often caused by consuing vast amounts of carrots or carrot juice. Some of the carotemoverdose is deposited in the fatty tissue beneath the skin.

Is the color of an orange an unreliable indicator of ripeness?

A series of cold nights can change the color of a ripe orangefrom orange to green. A series of warm nights can changecolor of an unpicked unripe orange from green to orange.

fruits and vegetables • . 141

;Morc,m'er, some naturally green rinds are orange because theyve been dyed orange.

y does lemon juice prevent discoloration ofavocado and potatos?

The discoloration of the exposed flesh is largely caused by oxidation, and ascorbic acid in the lemon juice slows down that process.'Another technique is to cook the food, because heat inactivatesili.e enzymes in the food that would otherwise bring about discoloration in the presence ofoxygen. (However, don't cook avocados,for the reason we explain in the next Q&A.)

should I not cook avocados?

When heated, avocados undergo a chemical reaction that produces unwanted, bitter-tasting compounds. That's why you seldom see hot avocado dishes on menus or canned avocado products on supermarket shelves.

a mushroom be too white?

e common supermarket-variety mushroom is bright white)Vhen harvested. By the time it reaches the produce bin or saladbar table, it will have developed a light-to-medium brown discol

ration. This is natural. What is not natural is for the mushroomn have a bright lily-white hue at this stage. That would indicatethat the mushroom was treated with the chemical sodium bisulfite to retard discoloration. This type of preserving agent cancause allergic reactions.

t causes boiledwhite onions or potatoes to turn yellow?

The whiteness ofthese vegetables, as well as that ofsalsifyand cauliflower, is due to the pigment flavone. When this chemical com

ound is subjected to prolonged heat or alkali, a brownish-yellowtdevelops.Several countermeasures can help keep your vegetables white.

and foremost, do not overcook them. Also, buy young, fresh

container

Botulism easily develops ingarlic staredin a sealed

at causes garlic to become bitter during storage?

Moisture hastens sprouting, which imparts a bitter flavor duringboth the storage and cooking periods. Keep your unpeeled garlicIn a dry, well-ventilated, and cool (but not refrigerated) place.Remember: Botulism easily develops in garlicstored in a sealed container, especially at roomtemperature. If you store peeled garlic in a jar,steep it in oil and keep it refrigerated. Make sureyou periodically open the jar. Discard the contents within ten days.

t shonld I lookfor when buyinggarlic?

heads if they have started to sprout or have exterior softThe fresher the garlic, the keener the flavor and the less bit-

any internal green sproutingwill be. Buy large garlic heads (relto their variety) because you will have fewer garlic doves to

Sweet onions cause fewer tears than standard cooking onions.Their higher moisture and sugar content lessens the quantity oftear-causing gas that is formed.

Some people are innately more susceptible to the tear-producing chemical reaction than others. However, the more frequentlyyou cut onions, the greater your tolerance. That's why the "crier" ismore apt to be a person who cuts onions only occasionally.

fruits and vegetables . • 143

does the inside ofa whole onion sometimes pop outwhenilit?

'The force that pushes the inside section of the onion out throughone of the polar openings is pent-up steam, To avoid this, give thesteam one or more extra escape routes by piercing the onion witha thin skewer before you add it to the water or stew. Another popular countermeasure is to make a l!4-inch-deep, X-shaped incisioninto the root end. ~atever technique you employ, simmer theonion, because boiling increases the chances of onion-pop bybouncing the bulb around the pot.

Why are onions cooked in butter more flavorful than those cookein water?

The butter not only contributes its own distinct flavor but lets ycook at a temperature higherthan 212°F.This increase helps eXI?some of the raw onion vapors. It also chemically converts some'the onion molecules into new, sweet-tasting ones, Butter, beinfat, also captures more of the desirable onion essences that wootherwise dissipate into the air.

What brings tears to my eyes when I chop onions?

When you chop or slice an onion, you release a gas, the lachrymtor agent propanethiol S-oxide. It wafts upward and chemically racts with the water in your eyes to form sulfuric acid. Your bodreacts defensively: Tears are produced to expel the irritant.

When a recipe c:alls for sauteing both onions and garlic, why is itessential to add the garlic near the end of the sauteing process?

If you saute the garlic for as long as is required for the onions, ywill certainly burn the garlic, producing a bitter flavor. Ifshorten the sauteing time of the onions to accommodate the glie, your onions will be insufficiently cooked, giving your dishraw, unsweet, oniony flavor.

vegetables in good condition. If your pipes carry hard water, t

adding a touch of cream of tartar or lemon juice to help neutralizits alkalinity. The more of these acids you add, the whiter yoboiled vegetables will be, but do not add so much that the flavorthe whitener becomes undesirably obvious.


Why is the onion family so widely used in cooking?

Onions, scallions, shallots, and other dan members do more thadd flavor of their own. Just as their volatile oils can irritate yoeyes, they can irritate your taste buds and olfactoreceptors •...plus if kept within bounds because when slightly teased, these agans tend to be more sensitive to flavors and scents of foods.


peel per-volume of chopped garlic and chopping will be easieEven more important, your stored garlic supply will not dry outfast.

If you buy elephant-type garlic because you do not relishstrong garlic flavor, consider buying regular garlic and using 1of it. This will save you money and reward you with a more enticing garlic aroma and flavor.

Should green-tinged potatoes be left in the supermarket'sproduce?

Yes. The green surface blemishes are caused by overexposure tlight. The tainted areas will taste bitter and contain at least SOlD

level of toxic solanine-not enough to kill you, but enoughtmake you think twice about eating ol}e of these tainted tatersPotato sprouts contain this same chemical-avoid them.

Whyshouldn't a raw whole potato be stored in the refrigerator?

The cold environment ~f the refrigerator encourages excessiconversion of the potato's starch into sugar. This chemical procmakes the tuber uncharacteristically sweet.

Why are the McDonald's and Burger King French fried potatoesthinner than the norm?

More than consumer preference is involved. Since the raw, precpotatoes are shipped and stored frozen, much of the starch invegetables converts to sugar. That extra sugar means thatFrench fries brown faster when cooked. Iffast-food establishmenserved the 50,percent thicker, normal-sized American French frietheir product would be either too brown on the outside or under;cooked on the inside.

Whyare new potatoes better than Idaho and other maturepotatoes for making potato salad?

Because new potatoes have more moisture and a lower starchtent, they will absorb less of the cooking water, as well as less

fruits and vegetables • . 145

mayonnaise or vinaigrette dressing. Therefore, new potatoes willbe less likely to break when the salad is mixed and served. Just asimportant, because it is not so thoroughly absorbed, the sauce hasnot as much opportunity to overpower the more delicate flavor ofthe potatoes. When less of the sa}lce is absorbed, we consumefewer calories.

are Idaho and other mature potatoes better than newotatoes for baking and frying?

Mature potatoes are drier, starchier, and mealier than new potatoes, so they will become fluffier and lighter-textured when baked.And since mature potatoes contain less water, there will be lesssplatter when they are fried in hot oil.

at causes a "hollowheart" to form inside some bakingtatoes?

The empty space in the center of a baking potato is usually the result of a potato growing too fast. The cells in the center of the potato move outward, leaving a hollow. Not to be confused with hollow heart is internal blackish rot or fungus growth, which shouldbe completely removed.

should potatoesbe pierced before theyare baked?

'A. pierced baked potato will have a better texture-mealy ratherthan soggy-because more of its moisture can escape. Even people who prefer soggy-textured baked potatoes should pierce thepotato deeply at least in one spot. Otherwise, the trapped steamcan explode the potato.

is it imperative not to overcook or overwork mashedtatoes?

Both excesses rupture many of the potato's cell walls, allowingmany starch granules to escape from their cellular prison. Thesegranules, which have become gummy during the cooking process,

uT


give your finished mashed potatoes a pasty, rather than a flconsistency.Yourpotatoes will be airier if you mash them in ave.tical rather than stirring motion-and ifyou don't perform thtask until just before serving time.

Whatever you do, don't try to mash potatoes in a food procesor. Its sharp and fast blades can rupture the cell walls soand effectivelythat you'll end up with gluey potatoes in practicalfno time.

Why are leftover potatoes better than fresh ones for makingpan-fried potatoes?

You can't cook raw potatoes at as high a temperature as youpreviously cooked potatoes. If you did, the outside of the P0tatpieces would be burnt before the interior was properly cookeThis problem doesn't exist for leftover potatoes because their intriors don't need cooking. The advantage ofpan-frying potatoesa fairly high heat is to minimize the development of a stickyof starch on the surface of the potatoes. This substance canthe individual potato pieces to stick to the pan and breakwhen you try to dislodge them.

Why should I soak potatoes before French-frying them?

If the surfaces of the cut potatoes are too dry, a sticky layerlatinized starch will develop on the exposed flesh soon afterpotatoes are put in the hot oil. This can cause the potatoes to stito each other and the pan. For best results, soak the freshly cut ptatoes for several minutes in ice-cold water. Rinse them brieunder a fast' stream of cold tap water and drain them in a sior colander. This step removes some of the surface starch.them dry with paper toweling-you don't want any wadroplets clinging to the potato surface lest the hot oil splawhen you lower the pieces into the pan. Promptly add the pottoes to the preheated oil before their surfaces lose their .ing moisture.

fruits and vegetables • • 147

do fruits like apples, pears, and peaches sometime have mealyes?

Such fruit was likelyharvested before ripening and stored in a coldWarehouse environment for weeks, if not months. This extends

e fruit's availability but degrades the fruit for the customer.

y should combe eaten as soon as possible after it is picked?

chemical reaction converts the sugar in the corn into starchd the longer the corn is off the stalk, the greater the conversion.

om connoisseurs can detect the drop in sweetness within anour after harvesting, which explains the rationale for this seem

iIlgiysnobbish recipe: Don't pick the corn until a pot ofwater, notore than a minute's run from the cornfield, is boiling.Heat also affects the conversion process. The higher the tern

erature ofthe ear, the faster the chemical reaction occurs. For thiseason, unless you intend to cook the corn immediately, refrigerte it as soon as it enters your kitchen.

shouldn't I boil com in saltedwater?

able salt is not pure sodium chloride. It contains traces of otherubstances, including calcium, an element that can toughen the

. of corn kernels during cooking. That is why it's generally aood idea to let your guests salt their corn on the cob at the table.ot only can they suit their individual preferences, but the corn. be more tender.In any event, the toughening effect of table salt is not as pro

ounced today as in decades gone by. Modern salt-processingchniques remove much of the calcium before the product

eaches the supermarket shelf.

does popcorn pop?

the popcorn kernel is heated, its internal moisture converts toeam. The steam pressure increases gradually until the kernel's

cture is no longer capable of restraining the pent-up steam. At


that split second, the kernel explodes, forming the characterisfluffy morsel. Ordinary corn doesn't explode like popcorn becait has a lower internal moisture content and a weaker structure,the steam pressure cannot build up as much.

For obvious reasons, popcorn must be popped in an endoscontainer. However, once the corn is popped, the lid should bermoved or the popcorn bag opened promptly lest the popcornabsorb some of the released steam trapped in the chamber. If thhappens, the popcorn will lose some of its crisp texture.

Another rule for successful popcorn is to store the unpopppopcorn in an airtight container. Otherwise, the kernels will lasinternal moisture and, hence, popping power.

Why do cookbooks recommend soaking carrot and celery sticksicewated .

If these vegetables are less than fresh, they may have lost sometheir crispness. Soaking them in ice water returns some ofcrispness because the food cells regain some of their lost wathrough osmosis. The water absorption re-swells the individcells, causing them to press against each other and once amake the eutire structure of the food more rigid and therefcrisper. The fact that its temperature is lowered by the ice waalso helps crisp the tired vegetable, but to a much lesser extethan osmosis.

If the vegetables are fresh-as they should be-soaking \\'have the opposite effect: They will lose a bit of their crispnesscause of water buildup between the walls of the already plucells. For some relatively dry vegetables like carrots, however,scant loss is more than compensated for by the pleasant timparted by the extra moisture.

Is tofu fat-free?

Many diners are under that impression, but tofu (bean curd)hseveral times more total fat and twice as much saturated fat asequivalent weight in skinless chicken breast. To be fair to tofu,us point out that it has only half the total fat and saturated fat

fruits and vegetables . • 149

ofa skin-on chicken leg serving of the same weight. Compareto red meats and it seems like a fat-watcher's dream food.

t is textured vegetable protein?

TVP, as it is known, is a meat substitute. More often than not, theproduct is manufactured from soybeans, because this Asian staple- unlike the other popular legumes-contains all eight essentialamino acids and can be easily molded into any desired shape.

Compared to meat, TVP has fewer calories and less saturatedfat. On the negative side of the coin, the color and flavor additivesin TVP-based products, like artificial bacon bits and meat extenders, can produce unpleasant tastes, smells, and textures. Soybeanbased TVP can also foster flatulence.

are young zucchini, cucumbers, eggplants, and other fruitetables better than those that are larger and more mature?

Most fruit-vegetables reach the first stage of maturity before theyhave completed their growth. Ifharvested then, they are more tender than if allowed to grow to their maximum potential size. Because of changes that occur in cellular structure as the cell waIlsbegin to thicken, the food toughens appreciably. At the same time,the woody cellular substance lignin, which cannot be softened bycooking, becomes more abundant. Fully mature fruit-vegetableshave another undesirable quality: more seeds.

Despite the superiority of young mature fruit-vegetables, supermarkets usually stock the fully grown ones. Profit is the motive.On a pound-per-pound basis, it costs less to grow the biggies because of labor savings. The fully grown specimens sell better, too,because most American shoppers associate largeness with quality.

y do most of the mass-marketed tomatoes have inferior flavordtexture?

These tomatoes have a relatively bland flavor and a cottony texturebecause commercial growers harvest their produce prematurely,and so the tomatoes are still very green, immature, and unripewhen picked. This practice reduces spoilage losses because the


tomatoes are less fragile and are therefore better shiippersbeing less perishable, they are marketable longer.

The tomatoes are red when they reach the store becausefood industry artificially turns them red by gassing them with eylene. If they had been left on the vine to ripen naturally, thwould have generated their own ethylene gas in time enough!trigger the color change. Though both artificially ripened an.vine-ripened tomatoes are red, those that are reddened by naturhave significantly better flavor, aroma, and texture.

Howcan I use the ripening effect ofethylene gas to my own advantage at home?

Sometimes your produce merchant's entire supply of fruits sueas apples, avocados, and peaches is unripe. This is not an intolerable problem as long as the fruit is not more than slightly unriand you give it time to ripen further. The additional ripeningmake the fruit taste sweeter because some of the starches willbchemically converted into sugar. In addition, the fruit will likellose acidity, making it taste comparatively sweeter. But if youthese fruits finish their ripening process at home, you run the riof having them spoil before they become fully ripe. Your best soltion is to hasten the ripening process by harnessing the ethylemgas that the fruit naturally generates. Rather than letting the gdissipate into your kitchen air, trap it by placing the fruit inpaper bag. The ethylene gas becomes concentrated and therefoaccelerates ripening.

Be sure to pierce the bag with a half dozen or so well-distriuted pencil-sized holes, for in order to stay sound, your fruitslike you - need to "breathe:' Like animals, they take in oxygeand expel carbon dioxide (though the nonfruit part of the piadoes the exact opposite).

Whyshouldn't you serve tomatoes cold?

They won't be as aromatic and savory because cold hindersconversion of the vegetable's linolenic acid to Z-3 hexenel,

Iruits and vegetables • . 151

compound that accounts for much of the desirable ripe-tomatoscent and taste. Cold also reduces the volatility of molecules andtherefore the number of Z-3 hexenel molecules that will reachyour olfactory receptors.

Another way to foster Z-3 hexenel development is never toplace store-bought tomatoes in the refrigerator when you returnhome from the market (as most shoppers do). Instead, allow thetomatoes to ripen at room temperature for several days. They willbe considerably more delicious.

apple seeds contain poison?

Apple seeds do contain cyanide, a deadly poison. But this shouldn'tstop you from enjoying apples, because the quantity of cyanide inthe seeds is minute. Even ifyou were to swallow hundreds ofseeds,the cyanide would pass through your digestive tract intact becauseit is encased by the seed's hard shell, which is impervious to the effects ofboth normal cooking and gastric juices.

Certain other seeds, including those of apricots and peaches,also contain traces of cyanide in their kernels. Since these seeds dooccasionally split open, the eater is often exposed to the cyanide.'!'he quantity of poison in one split seed, however, isn't a seriousthreat to a healthy person.

one end ofa fruit sweeter than the other?

The blossom end is generally sweeter than the stem end because itusually develops more sugar. Prove this phenomenon to yourself:Cross-taste opposite ends of an orange segment.

. ' .

•e people fantasizing when they claim they can tell the sex ofamato or an eggplant?

We have met many shoppers who brag that, by examining the sizeofthe scar on the blossom end of the fruit, they can tell the "boys"from the "girls" and therefore determine which tomatoes and eggplants have more seeds. Though there tends to be a positive correlation between the smallness of the scar and successful seeddevel-


opment within these fruit-vegetables, the scar size cannot haanything to do with their sex because these foods are botaniperfect. The term "perfect" signifies a life form that can self-ponate. Scar size can relate to the number of seeds in the food bcause when self-pollination occurs under less than optimum cicumstances, seed development is below par and the scar sizelarger than usual. A few fruit and vegetable buyers also errneously claim that they can ascertain the sex of other perfecplants such as pineapples.

Some fruits and vegetables, however, are either male or femal-the asparagus is an example. Nonetheless, the difference is nreadily apparent to the naked eye at the marketplace becausetelltale sexual characteristic (pistil, as opposed to stamen, develoment) is not conspicuous at the stage of the food's maturity wheit is harvested.

uces andthickeners

are the basic ways to thicken sauces and other liquids?

cook can thicken them by raising the ratio of solids to liquids,cooling them, by using a thickening agent, or by employing a

combinarion of these alternatives.

I raise the ratio of solids to liquids?

ou can accomplish this in several ways. One procedure, whichchefs call "reduction;' is to boil the liquid for a period of time'so that some of it evaporates. (Many recipes, especially those ofthe classic French cuisine, advise the cook to reduce the liquid toone-half or less of its original volume.) Reduction does morethan thicken. It concentrates existing flavors. And the Maillardreaction (see p. 33) precipitated by heat chemically creates newflavors.

Another popular technique for thickening a sauce is to introa quantity of minute solids, such as pureed vegetables, into

preparation; the more water-absorbent these food moleculesthe thicker your sauce becomes.

153

ails and fats • • 189

TryThis ButteredMeat Experiment

Buy two identicol steaks. Call them Aand B. Grill or barbecue them.Aminute before they are done, liberallybrushthe top of steak A (but notsteakB) withbutter, Cross-taste A and B.Which has the better flavor? Whichseems moretender?

does fat make some meats taste better?

does more than add flavor and keep the cooking meat moist. Itmeat more succulent because fat spurs salivation. It also lu-

baked goods be made with oil?

ne of the failings of oil is that, unlike fats such as butter and lard,l( is inclined to collect instead of remain uniformly distributedthrough the baking dough. For that and other reasons, your baked

oods will tend to be too grainy, an effect that is undesirable exept in a few specialties. Fat givesyour baked items a fluffy, moistexture and, as a bonus, a commendable flavor.

We do not recommend the all-purpose oils, the type that havebeen engineered to be suitable for both baking and deep-frying.

hese products do not give the best of both worlds: good bakingroperties plus a high smoke point for deep-frying. In order toivethe oils improved baking quality, the food manufacturer muste additives that appreciablywer the oil's smoke point.

all-purpose oil, therefore,compromise, noticeably

erior both to regular oilsor frying and to fats foraking purposes. No matterow hard the food technolo.sts may try, their laboratoryuest for a truly all-purposeil will be futile.

is exactly that. The phrase "pure shortening" means that either\\"UTI<ll. or vegetable fats, or both, could have been used. If the

ord "pure" is missing, the manufacturer has included additiveso lengthen the shortening's storage life or improve some of its

oking properties. Those additives, unfortunately, lower thesmoke point.

and fats

Is an oil a fat?

To a scientist, an oil is a fat, However, it is common culinarytice to use the term "fat" for those fats that are in a solid state wat room temperature. Those that are liquid at room temperatuare called oils.

Fats from animals are solid and, generally, fats from vegetablare liquid at room temperature. The notable exceptions are veetable oils from the coconut and palm kernel. Chemically speing, there is less difference between animal and vegetable fats thmost people would suspect. Even though their saturationcholesterol profiles do differ, both fats are made up of a glycemolecule linked with three fatty acids. They share the attributes §being water-insoluble and having a greasy feel.

What is shortening?

Shortening is classifiedas a fat because it is solid at room temperture. Shortening can be made with animal or vegetable fats, orcombination of them. Those based on vegetable oil are madeby hydrogenation.

Read the label. If it says "pure vegetable shortening:' the

188

at is the structural difference between saturated, monosaturated, and polyunsaturated fat?

A fat or oil is composed ofone glycerol molecule linked with threefatty-acid molecules, hence the umbrella name triglycerides. Afatty-acid molecule is a chain of carbon, oxygen, and hydrogenatoms. The length and makeup of this hydrocarbon chain canvary, but there is a maximum number of hydrogen atoms that

a vegetable oil or margarine that"contains no cholesterol" idealr cholesterolwatchers?

Many shoppers assume that if they buy a vegetable oil or margarine whose label says"contains no cholesterol" they run no riskof raising their serum cholesterol level. For the record, since cholesterol comes ouly from animal sources, these two vegetablebased foods never did contain cholesterol. Therefore, the shoppershouldn't be paying attention to the manufacturer's claims aboutcholesterol. He should be minding whether the product contains afat called trans fatty acids, and if so, how much. Trans fatty acidsare a major contributor to heart disease (more on this topic later).

oils and fats .• 191

membranes and sex hormones. You can get your necessary supplyofcholesterol from your liver (where it is produced) and by eatingfoods of animal origin: meat (especially fatty cuts and organs),dairy products, and eggs.Although your body needs some cholesterol, an excess amount in your arteries can cause coronary heartdisease and premature death.

If your serum cholesterol level is below 200 miIIigrams perdeciliter ofblood, you probably don't have to be concerned aboutlowering your level because you're classified in the "desirableblood cholesterol" group. Ifyour level is between 200 and 239, youshould give serious attention to reducing your level because you'rein the "borderline high blood cholesterol" group. If your level is240 or above, you're classified in the "high blood cholesterol"group-and failure to go on an immediate and strict cholesterollowering diet would be foolish ifnot ultimately fatal.

Cholesterol'

essential forbodily fundiincluding rhbuilding ofmembranes

sex hermen

Is cholesterol unhealthful?

Cholesterol, an alcohol, is not a dire threat togood health per se. It is essential for bodilyfunctions, including the building of cell

bricatesthe meat's muscle fibers, making it easier for yourtear the fibers apart.

Butter is the best fat for improving the flavor of steaks, asrestaurant chefs know. They brush steaks with melted butterbefore removing the meat from the heat source.

Is fat consumption unhealthful?

We must eat fat to stay alive.What is unhealthy is over-andconsumption of fat. Thanks to the barrage of warningsmass media, most people know the dangers associated withtoo much fat: obesity and coronary heart disease, to nameHowever, overcautious people who go to the other extreme (cosuming as little fat as possible) unwittingly risk their healthother way.

Fat is the vehicle that transports fat-soluble vitamins (A, D,~and K) through the body. If your body has used up its storedand carbohydrates and does not have a fresh supply of fat as,energy source, your body is forced to resort to its supply of ptein, an organic compound that is far better utilized for othersions, such as building body tissues. However, fat, too, hasbuilding chores: It is essential for cell development. Besides itstritive value, fat adds flavor and interest to prepared dishes,because it takes longer to digest than protein or carbohydrates,helps keep the stomach satisfied between meals.

Authorities say that 30 percent of a normal adult's calor'should come from fat. In practice, the figure is much higherfthe average American. Consequently, mostAmericans need not fret about a fat shortagein their diet. They should worry about theother peril, excessfat intake.



each carbon atom can have. If the molecule has. its full capacity 0

hydrogen atoms, it is called saturated. The diagram below depictthe middle ofsuch a molecule:

¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥"'-y-y-y-y-y-y-y-y-y-y-y-y-y-y-y-y-'"

HHHHHHHHHHHHHHHH

Otherwise, the molecule is unsaturated (the number of missinhydrogen atoms is always divisible by two). If the molecule has eiaetly two fewer hydrogen atoms than it is entitled to, it is callemono-unsaturated. Notice the double bonding of two carboatoms and the corresponding absence of two hydrogen atoms:

¥¥¥¥¥¥¥ ¥¥'H¥¥¥"'-y-y-y-y-y-y-y-y~y-y-y-y-y-y-y-y-'"

HHHHHHHHHHHHHHHH

If the molecule has room for four or more extra hydrogeatoms, it is called polyunsaturated:

¥¥¥¥ ¥¥¥¥ ¥¥¥¥"'-Y-r-Y-Y-Y~Y-Y-y-y-y-y~y-y-y-y-y-'"

HHHHHHHHHHHHHHHH

Animal fats contain a lot of saturated fatty acids, some monounsaturated fatty acids, and scant amounts of polyunsaturateacids. Except for the tropical oils, the opposite is true for vegetabloils.

Why is saturated fat unhealthful?

Saturated fat forces the liver to produce more low-density lipoprtein (LDL), a microscopic vehicle that carries cholesterol throuthe arteries. LDL promotes buildup of atherosclerotic plaquedeposits on the artery walls that inhibit blood circulation.buildup can cause a stroke or heart attack.

oils and fats • • 193

Cholesterol watchers are warned not to buy products with highcontent if the label merely states "pure vegetable oil" rather

listing the oil's specific name.r'Pure vegetable oil" is likely tomade in large part from highly saturated coconut or palm oil

because they cost less than the widely availablemono-unsaturatedpolyunsaturated oils. Nondairy creamers, in general, are an

source of highly saturated oils parading under the "purevegetable oil" banner.

yare mono-unsaturated and polyunsaturated fats consideredneficiali

Neither fat fosters the production of excessLDL. In fact, both tendto lower the amount ofLDL in your body. Keep in mind, however,that since both are fats, they become unhealthful if excessivelyconsumed.

.ch fat is better, mono-unsaturated or polyunsaturated?

A couple of decades ago scientists believed that the polyunsaturated kind was more desirable. Now researchers are voting for themono-unsaturated variety. Like polyunsaturated fat, it decreasesthe amount of LDL in the bloodstream. Unlike polyunsaturatedfat, it doesn't decrease the amount of high-density lipoprotein(HDL) in the bloodstream. HDLs are highly beneficial becausethey tend to remove excess cholesterol from the circulatory system. This helps explain why olive oil has become the pet amonginformed cholesterol watchers-approximately three-fourths ofits oil is mono-unsaturated.

a 100percent peanut or other vegetable oil free ofsaturated fat?

Just because a vegetable oil is classified as mono-unsaturated orpolyunsaturated doesn't mean it doesn't contain saturated fats.This classification is based on the predominant oil. All oils are acombination of saturated, mono-unsaturated, and polyunsaturated oils.What's most important to the cholesterol watcher is thepercentage that is saturated. The worst offenders are the tropicaloils, including the widely used coconut and palm kernel oils.They


from the People's Republic of China. Though oolong teas cangood, a great specimen has yet to be produced:

For a strong tea, which is preferable, a longer steeping period ormore tea leaves?

If you prefer strong but not bitter tea, increase the amount ofteleaves, not the steeping period. The longer the water and tearmain in contact, the more bitter your drink will be because mepolyphenols are extracted from each leaf.

Why is it necessary to cover a steeping cup or pot oftea?

The lid does more than minimize the water's heat loss. It also tntsteam, which dampens any unsubmerged tea leaf and sends itthe bottom. .

Another wayto prevent heat loss while steeping is to preheatcold teapot by pouring plain boiling water into it and lettingcontainer stand for sever!!l minutes before discarding the water.

Should I add milk to tea?

If a brew is of mediocre quality, you may have a scientific reasfor adding milk. Mediocre teas tend to be more astringentthquality teas. Milk lowers their astringency because some of thetringent tannic acids in the brew bind chemically with the miprotein 'molecules. And there is another benefit: With fewer frtannins, tea is less constipating. However, tea connoisseursright in saying that adding milk to a quality tea is equivalentputting ketchup on caviar because the milk masks the tea's subaromas and flavors.

What's wrong with drinking milk directlyout of the carton?

Hygiene is the obvious consideration, especially for other peopwho may subsequently drink the milk. However, even if oulyoperson will be drinking the milk, he might be affecting hisbecause he will be decreasing storage life. A human's 111<'U'11

repository of many forms of bacteria that can sour thematurely.

beverages • . 233

ill a store-bought container oforange juice last a week in therefrlgerator once its sealed cap has been opened?

Because of its high acid content, the juice should still be potableafter a week in the refrigerator, but its nutritional value will suffer.Oxygen enters and circulates inside the container each time thejuice is poured-and oxygen is the primary agent that destroysthe sought-after vitamin C content in the orange juice.

food storoge . . 235

the other major food preservation methods work?

Drying (removing up to 99 percent of the food's water content) isan effective preservation method because no known form ofearthly life can thrive without water. Enzymes, too, are thwartedwithout a sufficient H20 supply.Since desiccated foods can readilyassimilate moisture from the air, it is advisable to store themtightly wrapped in a low-humidity environment. Placing the foodin a cupboard near a stove is not the answer because water molecules from the steaming pots can be greedily absorbed by the"thirsty" food.

Freezing kills microbes or inhibits their growth. With freezedrying, the selected food is frozen before its water content is removed. The water is first changed to ice and then directly intovapor, a process called sublimation. The middle phase of normalfreezing,liquidity, is skipped.

Salting (curing) draws much of the moisture from the food either by simple absorption or by osmosis. Salt also creates an adverse environment for microorganisms. One salting technique isdry-curing: The food is coated or buried in salt.A second populartechnique is to immerse the food in brine, a salt-and-water solution. A variation of the second method is to inject brine into thefood, for instance, by pumping the saline solution through theblood vessels.

Pickling involves treating foods such as cucumbers with vinegar or other acidic liquids that are hostile to the well-being ofmicroorganisms. A pickling solution usually also contains water,sugar, salt, and spices;certain chemicalscan crop up in the formulaas well.Marination is, among other things, a pickling process.

Refrigerating a food will not kill most of the microorganismspresent, but it retards their growth enough to preserve the food.

tend to retain more of their flavor, color, and texture than thosethat have undergone more conventional storage and cookingmethods because less cellular rupturing occurs.

ood storage

234 •

Are sous vide foods safe?

The sous vide (French for "under vacuum") food preservation'method was invented by the French in the 1970s.Although it iswidelyaccepted in Europe as being safe and practical, many Americans are concerned about health risks. They shonldn't be. Thefood is slowly cooked and sterilized in a sealed vacuum pouch,then quick-chilled and refrigerated, usually for a maximum 4several weeks. The pouched food is reheated in simmering watebefore it is opened and served. Sous vide fruits and vegetable

What is irradiated food, and is it safe?

Irradiated food has been bombarded with ionizing radiation tohelp sterilize it and extend its shelf life. This radiation treatmenkills harmful bacteria and destructive insects-and can eliminatthe need to use chemical sprays. Some people mistakenly believethat irradiated foods are radioactive. Just as radiation does not remain in microwaved foods, radiation does not remain in irradiated foods. Many leading health organizations say that irradiatedfoods pose no serious health risks.

Try This Meat FreezingExperiment

food storage • • 237

Buytwo identical steaks to test the effect of freeZing on meal. Call the steaksA and B. Freeze A and refrigerate B.After A is frozen (typically about 8 to12 hours), completely thaw it in thewarmestpart of the refrigerator(normally takes 10 to 1B hours). During thisthawing period, store Bnext to A.When A is thawed, bring both A and B

to near room temperature. (This willtake about an hour.) Grill or saute Aand B.Cross-taste. Which steak is

mushier?

freezing diminish the quality of food?

answer is an undeniable yes. When the frozen food thaws,some of its stored water seeps out of its cells, and consequentlythe cellslose their plumpness and the food its firmness. The waterloss is caused by the creationof ice crystals and the loss ofosmotic capability.

Osmosis, in simple terms,is the natural passing of liquid through a semipermeablemembrane (in this case, thecell wall) to equalize the concentration of liquid on bothsides of the membrane. Sincethe dissolved solids inside thecell make the water in the cellmore concentrated than thaton the outside, water will flowinto the cell, swelling it inthe process. The swelling increasesthe pressure ofone cellagainst the other, and thereby the food's rigidity. Freezing, however,diminishes the osmotic capability of the cells, and thus theircapacity to absorb and retain water.

such as marinating, have been taken to make the food unfavorableto bacterial growth.

It is important to note that we use the phrase "most bacteria:'There exist certain cryophilic (cold-loving) bacteria and other microorganisms that can do nicely,thank you, at temperatures below60°F. Likewise, our world has thermophilic (heat-loving) microorganisms that flourish at temperatures above 125°F. For these rea-

more cautious experts place the danger zone between 40°l40°F-and some expand the temperature range even fur

ther.

Predicting a food's refrigeration life is not an e",\,ct science.dozen variables affect it: the kind of food; how the food wassoned and processed; the freshness and condition ofthe food; hothe food was wrapped or covered; the refrigerator's temperatu(ideally 35° to 39°F, or 2° to 4°C); the location in the refrigerat(the rear wall is colder than the door shelves, and the area nearesthe freezer unit is colder than the crisper); and how often anfor how long the refrigerator door is opened. The following arrough, conservative guidelines for several popular foods in the.'fresh, uncooked state: seafood-one day; ground meat-oilday; other meat - two days;and milk - four days.

Freezing, of course, is an even better deterrent than refrigeration. For optimal results, a freezer's temperature should be nohigher than O°F (minus 18°C),a level that is beyond the capabilitY!of the freezer compartments iIi the majority of home refrigerators. Enzymatic reactions continue at low temperatures, althouat a very slow pace, and they do not cause problems except whefreezing fruits and vegetables. (See "Why must vegetables bblanched before freezing?"later in this chapter.)

Canning requires two major steps. The first is heating the foohot enough and long enough to kill most of the microorganismand all of the potentially more dangerous ones, such as the baCtterium Clostridium botulinum. The second step is sealing the f094in an airtight, sterile can or jar to protect the contents from anonslaught by a new supply of microorganisms or oxygen and tkeep the food from drying out.

Sugaring is another preservation technique because sugar creates a hostile environment for bacteria. Smoking does the same ffoods like hams.

What is the temperature "danger zone" for bacterial growthin foods?

According to the U.S. Department of Agriculture, most bacteriathrive at temperatures between 60° and 125°F. The growth ofcroorganisms will be prolific unless other precautionary


that an individual home unit freezes food as quickly as possible.Avoid overloading your freezer, because crowding prevents coldair from circulating properly. When possible, add only a fewroom-temperature items at a time to a partially filled freezer because a large volume of unfrozen food will appreciably raise thefreezer's temperature and capability, and some of the food alreadyin the freezer is likely to partially thaw and then refreeze, forminglarger ice crystals in the process.

Does a chest freezer have an energy-savingadvantage over an upright freezer?

A chest freezer will not lose as much cold air each time you open itbecause cold air is heavier than warm air. The cold air in the four-

Is a full freezer more energy-efficient than a half-empty one?

It uses less energy because frozen foods retain cold far better thandoes air. As a bonus, your food will stay frozen longer in the eventof a blackout. Don't, however, keep your refrigerator full. Air circulation is essential.for helping preserve the scent and freshness ofsome nonfrozen items.

food storoge . • 239

Are there some foods that are less suitable for freezing?

As people who have sprinkled salt on icy sidewalks know, saltlowers the freezing point of water. So if a prepared food has beenpresalted (most have), the food will not freeze as well as it wonldif unsalted and will thus have a shorter minimum freezer storagelife.

Fat does not freeze as well as protein or carbohydrate and consequently has a shorter freezer storage life than its two companionnutrients. The implication is clear: If you plan to freeze a cut ofmeat for a long period, you would probably be wise to trim off allor most of its excessfat before freezing it.

Since salt pork and bacon are both fatty and salty,their freezingproperties are poor.

ing prevecold airlrocirculating

properly

Ice crystals, the second major cause of flabbiness, form inside!and around the cells when the food is frozen. These crystals take'up more space than the original water, and the expansion burstsmany of the cell walls and pushes some of the cells apart, givingthe seeping liquid an easy escape route.

The experiment on the previous page will conclusively provthat freezing does give a mushy texture to foodswith a relativelyhigh water content.

Another drawback to freezing most foods isthat when liquid flows out of the ruptured cellwalls, it carries with it some of the food's originalflavor and nutrients. Still another negative feature is that most frozen foods, if stored longenough, will pick up foreign odors from thefreezer. .

Some vegetables survive the freezing ordealbetter than meat, seafood, and fruit. Peas, spin-ach, and lima beans are among the vegetables that suffer the leastdeterioration (though, to be sure, some damage occurs). Vegetables like cauliflower and broccoli are poor freezers because thprocess ruins their desirable texture.

Why are certain freezing methods better than others?

The key to maintaining a food's quality is speedy freezing. Th.faster the food is frozen, the smaller the ice crystals that atformed in and around its cells.These tiny crystals do not cause amuch tearing as the larger ones formed by slow freezing. T~food's texture therefore will suffer less damage. Another relate.benefit is that the food-particularly meat-will not losemany of its juices during thawing because its cellwalls remain relatively intact.

Most commercial food processors quick-freeze their productby methods such as immersion in a cold solution or exposuretofrigid air blasts. The process is, of course, faster than any possiblein a home freezer.Yetthere are steps that can be followed to ens'!



walled chest has only one avenue of escape-upward. In contrast,cold air easily cascades out of an upright freezer each time you'Ipen its fourth wall, the door.

Why does chicken have a shorter freezer and refrigerator lifethan beef?

It has a higher unsaturated-to-saturated fat ratio. Unsaturated (especially polyunsaturated) fats are more prone to oxidation, andtherefore rancidity, because oxygen molecules can more easilybind with their molecules.

What is the best way to store surpIns pan juices?

Take advantage of a basic law of nature: Fat has a lower specificdensity than water, the principal ingredient of pan juices. Afterliquid fat and pan juices are mixed together, the fat-because ofits lower specific density- gradually rises to form a distinct upperlayer, while the pan juices .setde. Therefore, to store pan juices,pour them into a container, cool to near room temperature, cover,and refrigerate. When the fat layer has solidified, you can easily remove it, leaving the pan juices behind. However, we do not recommend removing the fat layer until you are ready to use the storedpan juices because the fat serves as a functional seal that helps prevent bacteria and foreign odors from reaching the juices as they sitin your refrigerator.

Why should I wrap meat tightly before storing it in the freezer?

Freezing does not halt evaporation of the meat's fluids, it ouly retards it. Therefore, if the entire surface of the meat is not carefullycovered with a moisture-proof (or at least moisture-resistant)wrap, some of the food's water, which is temporarily in a solidstate, will evaporate. This direct transformation from ice to vaporis termed sublimation and produces what cooks call freezer burn.

The meat's covering should be sealed securely to prevent oxidation and to help ward off rancidity. Although the fat in any meatwill eventually become rancid if stored long enough, the grace pe-

food storage • . 241

riod is certainly long enough for normal requirements if the foodis kept solidly frozen and not exposed to excess oxygen. A tightwrapping also helps prevent the meat from absorbing freezerodors.

Why should aluminum foil not be used to wrap food that is tobe frozen?

Aluminum foil usually helps maintain a food's temperaturewhether high or low-s-because it retards the transfer ofheat fromthe food to its surroundings and vice versa. Thus, a food protectedby foil will retain heat and not freeze as quickly as it would in, say,plastic film.

Although aluminum foil is not the best choice for freezing, youcan profit in other ways from its properties. Some examples: Afood, or section of a food, can be wrapped with foil for slow thawing. If serving must be delayed, you can keep a hot food warmlonger, or a cold food cool, in aluminum foil. Because a shiny surface reflects radiant heat, you can preserve heat by facing the shinysurface of the foil inward toward the hot food. By the same token,when keeping a food cold-perhaps for a picuic lunch- face theshiny side outward so it can reflect radiant heat away from thefood.

Whyshould I not wrap saltyor acidic foods in aluminum foil?

Salt and acids react chemically with aluminum, forming a powdery white substance on the surface of the foil and food. Thoughharmless in small doses, this coating is undesirable in terms of flavor and cosmetic appeal. If you want to take advantage of the storage virtues of aluminum foil, first cover the exposed food withplastic wrap.

Why does chocolate sometimes develop a white discoloration?

The bloom (as this discoloration is called) is almost always causedby improper storage and is usually one of two substances. It could


be cocoa fat that rose to the surface of a solid chocolate mixturethat was stored too long at room temperature. Or it could be sugarthat was drawn to the surface by the condensation of a looselywrapped, refrigerated chocolate mixture; the moisture extractssugar from the mixture's interior. In either case, the bloom is unaesthetic but harmless.

Why must vegetables be blanched before freezing!

Obvious changes in color, texture, and taste take place in a vegetable that is left out on a table or in the refrigerator. The veg-.etable's own enzymes are largely responsible for that transformation. The extremely cold temperatures of freezing slow down thechanges but do not completely stop them. In fact, some enzymaticactivity has been observed at minus lOOoP, and the temperature in.most home and commercial freezers is not below O°F.

Extreme heat, on the other hand, inactivates enzymes andsets color and flavor. For this reason, most vegetables should beblanched before they are frozen. The process involves partiallycooking the food in boiling water or steam for up to several minutes. Some cooks choose to boil or steam their vegetables as the)'would before serving. However, blanching is preferable to fullcooking because it does less damage to the vegetable's texture,color, and taste.

Why is sugar syrup customarily added to frozen fruits!

Fruits are also candidates for blanching as they, too, are susceptibleto deterioration caused by enzymes. However, a more effective aleternative to blanching fruit is to preserve color, flavor, texture, andnutrients by adding an antioxidant, such as ascorbic acid or sugarsyrup, before freezing. This technique deactivates enzymes and.blocks oxidation.

Sugar also serves at least two other important functions. Wh~#it comes to freezing, slightly unripe fruits are better than ripe ones,and sugar's sweetening power helps mask the acidic flavor in un-

food storage . . 243

ripe fruits. Sugar also lowers the freezing point and thus helps prevent the formation of large ice crystals that could rupture the

. fruits' cell walls and membranes. Punctured cells are undesirablebecause flavorful juices would seep out, making the texture mushywhen the mixture thaws.

Howcan I tellwhether a wrapped piece ofmeat sitting in thebutcher's displaycase has been frozen!

A large pool of juices in the tray package is probably a result of therupturing of cellwalls caused by freezing.

yare certain methods better than others for thawing meat?

Two primary aims when thawing are to minimize damage causedby the ice crystals melting in the meat and to avoid bacterial contamination as the meat's temperature rises. However, the cookfaces what seems to be a contradiction. On the one hand, rapidthawing canses more of the meat's juices to be lost and more deterioration in texture. On the other, rapid thawing-if done properly-reduces the threat ofbacterial contamination.

The problem can be resolved by transferring the meat from thefreezer to the refrigerator, where the temperature is high enoughfor the meat to thaw and cold enough to allow the process toprogress at a slow pace while preventing bacteria in and on themeat from increasing dangerously. Thawing in the refrigerator cantake as little as several hours for a thin steak or as much as severaldays for a colossal turkey.

Sometimes the cook does not have the time to defrost meat inthe refrigerator and must leave it out at room temperature. Thisusually doesn't present a problem if the meat is a thin cut, becausethe time it takes to thaw is not long enough to pose a health risk.But the surface of a thick piece of meat will completely thaw longbefore the inside and therefore affords ample opportunity for bacterial growth. If meat must be defrosted quickly and is a little toothick to risk thawing at room temperature, place it in a tightly


sealed waterproof bag and leave it in a tub or sillk filled with coldwater.

Wherever you choose to thaw meat, keep it securely wrapped asa precaution against moisture loss and contamination from the.environment.

We don't recommend thawing meat (especially a thick cut) in ~

microwave oven. The meat's exterior will be mushy and overcooked long before the meat's interior begins to thaw (a microwaveoven can heat molecules in the liquid, but not the solid, state).

Is it safe to refreeze a food?

Yes, if the food is not dangerously contaminated at the time of refreezing and is handled properly afterward. The only detrimentaleffect will be the one normally associated with freezing, a loss intexture and flavor-and it may he amplified.

The "do not refreeze" warning gained its prominence whenClarence Birdseye, the father of the frozen-vegetable-industry, included the phrase on his company's packages. Business logic stoodbehind his decision. Birdseye did not want to be held responsiblfor any mishandling once the product reached the consumer'hands. If the customer repeatedly removed a package from thfreezer, only to return it there after deciding it wasn't needed, th~

resulting textural damage would certainly discourage future sales,The frozen-food company also wanted to prevent customers froencouraging bacterial growth by subjecting the product to roomtemperatures for extended periods of time.

Some food writers interpreted the "do not refreeze" recommen;dation as a not-to-be-questioned health precaution, and the misapprehension quickly spread. We do not mean to suggest th~t

foods should be randomly thawed and refrozen. Caution shouldalwaysbe exercised, especially since the injuries a food suffers dUJ:ing freezing and thawing make it more vulnerable to deterioration. Generally,you can safely refreeze a food that still has icec~tals, or that has been no warmer than 40°F and has been out of thfreezer for no more than 24 to 48 hours. Shellfish and dishes COl:!

food storage • . 245

taining cream are among the foods that are particularly susceptible to bacterial growth. In most cases, they should not be refrozenonce they have thoroughly thawed.

Should I think twice about buying a frost-coated package offrozen vegetables?

Yes. This is too often a sign that the frozen food has thawed tosome extent at least once before you saw it. The source ofthe frostis usually moisture that has escaped from the food inside the package. But even if the ice crystals are caused by moisture from another package, its existence portends deterioration, because ifonepackage inside a shipping container has thawed, then chances arethat some of the contiguous packages have also.

Sometimes thawing occurs in the store's display unit. Our research in several dozen supermarkets indicates that the surfacetemperatures ofthe topmost frozen-food packages in open displayunits are sometimes above 32°F. We've also observed a similarproblem for refrigerated items like meat and milk that are storedin open display units. The temperatures of the topmost (or foremost) refrigerated packages are occasionally higher than theyshould be. This condition reduces storage life and probably createsa health hazard now and then. Moral: Select deep.

Are certain foods natural storage enemies?

Yes. Onions, for example, should never be stored with potatoesthey emit gases that negatively alter the flavor of the potatoes.However, some storage relationships are symbiotic, as is the casewith oranges and bananas. Oranges give off ethylene gas, whichaccelerates the ripening of the bananas.

Why shouldyou not store fruits and vegetables in sealed,airtight bags?

Fruits and vegetables are alive. Like animals, they breathe in oxygen and expel carbon dioxide. Eventually, in an airtight environ-


ment, they will use up all the available oxygen and suffocate. Damaged cells spell loss in color, flavor, texture, and nutrients.

Why should I not refrigerate jars ofdried herbs?

Condensation forms inside the cold jar each time you open thecontainer in the room-temperature kitchen. This moisture shortens the dried herb's storage life.

Why do I have to defrost my refrigerator less in the winter than inthe summed

The frost buildup comes primarily from the moisture-laden airthat flows into the refrigerator each time you open it. In winter,less moisture flows in because the room air is drier and you don'topen the door as frequently for ice cubes.and cool drinks. Delay'ing the defrosting chore can be expensive in this day of high en'ergy costs. The coating insulates the tubing, forcing the refrigerator to work longer to cool to the desired temperature.

Can a person cool a room byleaving the refrigerator door open?

We hear stories about people doing this when their air conditionerbreaks down on a sweltering day. Their solution is counterproductive. The room gets warmer because a refrigerator is not a 100percent-efficient machine-it produces more heat than coldness.Few people realize how much heat is expelled through the refrigerator's rear exhaust vent.

Why does a vacuum storage bottle maintain the temperature ofbeverages better than a thermal bottle?

The heat of a stored hot beverage is mainly lost to the colder airaround it through conduction, and a cold beverage will graduallygain heat from the environment in the same way. A thermal ora.vacuum bottle retards the transfer of heat (in either direction) be?tween food and its surroundings by placing a poor heat-conducting medium between the two.

food storage . • 247

The basic difference between the vacuum and thermal storagebottles is the chosen medium. With a vacuum bottle, the mediumis a near-vacuum that is hermetically sealed between the unit'sinner and outer glass liners. In the case of the thermal bottle, themedium is a solid material that is a poor conductor ofheat, but notas poor as a near-vacuum. Consequently, the vacuum bottle moreefficiently impedes heat transference-and this capability is mostpronounced when storing a hot beverage. (Just in case there is anyconfusion, allow us to point out that the Thermos brand employs avacuum and not, as its name suggests, the thermal method.)

A thermal storage bottle does have a convincing selling point:It is less breakable, a pragmatic consideration when the user is alunch-toting child.

Whyis a pressure cooker a must for most home canning?

To kill the bacteria that can produce the deadly botulism toxin inlow-acid canned foods, you have two options. You can cook thefood at or near the boiling point for a ridiculously long time, aprocess that cooks the food to death before it kills the bacteria. Oryou can use a pressure cooker. Because a pressure cooker can reacha temperature ofabout 250°F,it better preserves the texture, color,flavor, aroma, and nutrients of the food by appreciably shorteningthe required cooking time.

Does an animal's state ofmind during its final hours affect thestorage life ofmeat?

Yes. If a mammal (or fish) is agitated, afraid, startled, or otherwisepsychologically disturbed, its body automatically starts to convertthe carbohydrate glycogen stored in its tissues into sugar for quickenergy. This natural biological reaction gives the animal greaterstrength to fight or take flight, thus increasing its chances for survival. However, should the animal die, any conversion that occurred will shorten the meat's storage life. After death, the glycogen remaining in the muscles converts into lactic acid, a substancethat retards bacterial growth. It follows that the lower the glycogen


level, the less lactic acid is produced, and therefore the shorteramount of time the meat will stay fresh. .

Everyexperienced deer hunter has heard the so-called cnesumuthat the venison will be more tender if the arrow or bullet istargeted, slaying the animal instantly. This advice is not onlymane but also sound, because if the deer struggles, runs, andters a state of shock before dying, it will use up much of thegen in its muscles. When this happens, the venison meat cannotsafely be hung for very long, and therefore it will not becometender as it should be.

For the same reasons, modern slaughterhouses kill-bean electric probe or whatever - with such surprise and swiftnessthat an animal barely has time to contemplate its fate.slaughterhouses go one step further and tFY to maintain anronment that is as serene as possible for the animal.

alth andnutrition

How many microbes live in a speck ofdirt?

Scientists estimate that a speck of dirt could contain millions ofmicrobes. Good reason for thoroughly washing an apple, celerystick, and any other fruit or vegetable you intend to eat raw.

What is the single greatest cook-induced source ofbacterialcontamination in the kitchen?

Usually it's the humble can opener. Although many cooks washtheir cutting board surface dutifully after each use, they forget todo the same to the can opener. Even if just one tiny food particlesticks to the blade, it can make an excellent medium for pathogenic microorganisms. These bacteria have ample time to multiply by the time the cook uses the can opener the next day.

Why shouldyou not set a hot pot on a butcher block or othercutting surface?

The primary harm is usually not damage to the cutting board surface but an increase in bacterial contamination. The board absorbsheat from the pot and can retain it for up to 30 minutes. During

• 249


this time, any pathogenic bacteria that are on the board willply faster than if the board were at room temperature.

Today chicken

meat is 1,000times more likelyto be contami.

nated with hcrmful bacteria thanpork with thetrichinae worm

parasite

health and nutrition . • 251

size, that are called trichinae. Although most people associatetrichinosis with pig meat only, other animal flesh, including deerand bear, can also be contaminated. After you eat infected meat,the parasites lodge and reproduce in your intestines. Their larvaeenter the bloodstream, travel to yo.ur muscles, and, while growing there, cause pain, fever, muscle deterioration, and sometimesdeath.

Trichinosis is not found around the entire globe. SoutheastAsians eat raw pork, and Europeans consume raw hams-for example, the celebrated prosciutto of Parma-without dire healthconsequences. In the United States, the medical profession nowadays sees relatively few cases of trichinosis, owing to increasedpublic awareness and the widespread adoption of precautionarymeasures. For instance, garbage-favored by trichinae and pigs-is now cooked before it is fed to the animals. Most municipalities have instituted laws requiring that butchers within their jurisdiction use a separate meat grinder for pork, or that they sterilizethe grinder before changing from pork to nonpork. In this way,the chance of contaminating other foods is minimal or nil. Government standards help assure the consumer that cured ham andprecooked sausages produced by responsible meat processors arefree of trichinae.

Today chicken meat is 1,000 times more likely to be contaminated with harmful bacteria than pork with the trichinae wormparasite. Still, whenever you eat any other American-producedpork, it is wise to assume that it contains livetrichinae, even though the actual chancesthat this is so are incredibly small. Why playwhat amounts to Russian roulette in thekitchen? Remember that a government inspection seal is no protection against trichinosis because the examiners do not check forthe microscopic worms. Take the same precautions that your butcher should: Nevertaste-test uncooked pork mixtures. Alwaysthoroughly wash your hands and any utensil

18

64512

4,00032,000

262,0002,000,000

16,000,000134,000,000

9:00p.M.

10:00 P.M.11:00 P.M.12:00 A.M.1:00 A.M.2:00A.M.3:00A.M.4:00A.M.5:00A.M.6:00A.M.

How fast do bacteria multiply?

In an ideal environment, a bacteria cell can divide approximatelyevery 20 minutes. The accompanying table illustrates the proliferation results over a lO-hour period. Of course, these are theoretical, not real-world results, as bacteria sometimes dividethan expected. But imagine what would happen if the stewoff, as is possible, with thousands upon thousands of bacteriacells.And some bacteria do more than divide. They produceins that can kill you or make you seriously sick.

Bacterial Grawth in a Single Bacteria CellDividingEvery 20 Minutes in a Meat Stew Lllft Out Overnight

Time Bacterial Count

Howdo some outdoor grillers unwittingly contaminate theircooked food?

They transfer raw meat from the kitchen to the grill on aLater they bring the cooked meat to the table on the same diswithout first washing it.

How does trichinosis attack the body? .

You can contract this disease when you eat pork or pork productsthat contain the live worms, round in shape and microscopic


that touches raw pork with hot water and soap ordetergent, If yougrind the pork, sterilize the machine with boiling water afterward.

See chapter 3 (p. 64) for cooking instructions regarding trichinosis.

Is an uncooked canned ham trichinosis-proof?

Federal law dictates that all ham must be cooked to an internaltemperature ofat least 140°Fbefore being canned. Since a temperature of 137°F kills the deleterious parasites, a can of ham is not athreat, whether labeled uncooked or fully cooked. (The latter mustbe cooked by the processor to a minimum interior temperature of148°E)

What causes botulism?

A person can be stricken with botulism after ingesting th~ toxinproduced by the bacterium Clostridium botulinum. The bacteriumcan form the toxin only in the absence of oxygen, so canned goodsand products like meat that are wrapped in airtight casings are potential sources ofbotulism.

The pernicious toxin is more likely to be generated in low-acidfood, such as mushrooms, peas, corn, or beans, than in a high-acidfood like tomatoes. However, some new tomato hybrids are notacidic enough to prevent the bacteria from creating the toxin, sohome canners beware. Food destined for canning must be heatedto a temperature high enough, and for periods long enough, to killany toxin-producing bacteria present.

If toxins have developed in a food that has been stored underanaerobic conditions, they can be made innocuous by boiling thefood for 30 minutes. Nevertheless, any suspect food productsuch as one with a swollen can or jar lid-should be discardeduntasted.

Botulism symptoms include malfunctioning of the nervoussystem. Vision, speech, and swallowing are impaired. Death resultsin cases where the respiratory muscles are paralyzed.

There is an antiserum, but there is a catch to its use: It is most

health and nutrilian . • 253

beneficial when given before the patient's symptoms are apparent,and most people have no idea that they have eaten contaminatedfood until they are physically affected. Once a person does exlubitsymptoms, quick diagnosis and treatment is crucial to survival.

What causes staphylococcalpoisoning?

"Staph," as this common food-borne disease is nicknamed, iscaused by a toxin produced by the bacterium Staphylococcus aureus. That microorganism creates the toxin most readily in the 40°to 120°F temperature zone, particularly in low-acid foods. Custard-filled foods are notorious sources ofstaph. Such foods shouldnot be left out ofthe refrigerator for long.

For the record, mayonnaise has been given a bum rap: It's notthe underlying reason chicken and other mayonnaise-dressed salads become contaminated under the hot sun at picnics. In fact, therelatively high salt and vinegar-lemon content of commerciallyprepared mayonnaise slows down bacterial growth. The real culprits are low-acid ingredients such as the chicken. (Please note,however, that homemade mayonnaise usually is too low in acidand salinity to retard the bacterial growth.)

are otner maier food-borne bacterial poisonings?

Salmonella bacteria are found in many foods, including raw meat,unpasteurized milk, and uncooked eggs. The disease-producingagent is the bacterium itself and not the toxins generated. E. colibacteria thrive in animal fecal matter on farms and can be transferred to cut-up meat in a processing plant. Shingella bacteria canalso come from fecally contaminated food

Does a special anti-impurity filter attached to the kitchen sink'swater tap orpipe do moreharm than good?

Unless you frequently replace the filter or thoroughly clean it, yourisk unsafe bacterial buildup. In some filtering systems, the bacteria multiply so rapidly that within a couple of weeks the numberof microorganisms that flow into your drinking glass may exceed


the quantity that would have traveled unhindered through yourtap.

Even ifa filter is changed frequently, there remains the questionof the effectiveness of the various brands. With most, the watergushes through the filter too quickly to trap as many microorganisms as the unwary buyer is led to expect. Perhaps an even moreimportant issue is whether your water supply is as dangerouslycontaminated with pathogenic microorganisms, additives, impurities, and other demons as some alarmists - and filter hucksters- claim. Check the local facts before investing in a filter apparatus.

Can I get lead poisoning from glazed potterykitchenware?

Each year a number of people die or become seriously ill fromlead poisoning caused by the lead that leaches out of improperlyglazed pottery kitchenware. .

By U.S. law, glazed pottery designed for culinary use must befired at a high enough tempera!ure to fuse the lead component ofthe glaze into the container permanently. Some glazed kitchenware pottery that is brought into this country illegally, or in thehands of returning tourists, falls well short of the federal standards. If used to store or cook foods (and especiallyhighly acidicfoods), the lead will likely migrate from the walls of the vessel tothose of the diner's stomach. This lead buildup in the body cancause damage to internal organs as well as to the immune, cardiovascular, and other systems. Children can also suffer learning andbehavioral disorders.

The type of tin cans that are sealed with lead solder are anotherpotential source of lead poisoning. It is a sound policy never tostore a high-acid food such as grapefruit juice in an open can. 111.stead, transfer the contents to a glassjar or similar unleaded, non,corrosive vessel.

Does chiciren soup help cure colds?

Yes, but this therapeutic magic is not chiefly due to its ingredientsas many people believe. The primary credit belongs to heat. Th

health and nutritian • . 255

higher the temperature, the more fluid the mucus becomes andthe more quickly it exits the respiratory tract. This is beneficial because mucus harbors cold-causing microbes. Chicken soup is notthe only remedy. Another hot liquid such as a cup of tea wouldalso serve the mucus-ridding purpose.

Ifyou do use chiciren soup, malre it from scratch. Commercialsoups and bouillon cubes tend to be very salty, to the point wherethe soup will partially dehydrate you. That would be counterproductive because when you have a cold, your body needs an extrasupply of water to combat and flush out the microbes and unwanted byproducts.

Can diet, cigarettes, or medication affect a person's vitaminrequirements?

Yes. What you put in your body can sometimes sap the strengthof certain vitamins or undermine your body's ability to processor manufacture them. Whenever this happens, you will probably need to consume more than the U.S. recommended daily allowance of vitamins (although these allowances are more thanample for most people).

Chain smokers, for instance, need extra vitamin C, and boozehounds and sugar fiends require more of the B complex vitaminsthan their moderate companions. Additional B complex vitaminsare also recommended for people using antibiotics for extendedperiods of time, and for women talring birth control pills (whoalso need extra vitamin C).

However, you need not offset a lack or loss of vitamins withsupplementary vitamin pills. Increasing one's intalre of fruits andvegetables usually accomplishes the same mission more efficiently.

Whyare manufactured vitamins no different from naturalvitamins as far as the bodyis concerned?

Most vitamins are actually surprisingly simple configurations ofbasic elements such as carbon, hydrogen, oxygen, and nitrogen,and they can be flawlessly duplicated in the laboratory. Your body


cannot discern any difference between, for instance, ascorbic acid(synthetic vitamin C) and rose hips (natural vitamin C) becausethe two have an identical chemical makeup. The argument for natural vitamin supplements is faulty-although lucrative. If youshop around for vitamins or vitamin-fortified foods, you will notice that the natural vitamins usually cost considerably more thanthe synthetic.

However, any vitamin supplement, whether natural or synthetic, is no substitute for a balanced diet. Scientists may be able tomanufacture the vitamins that have so far been identified, but theyhave neither the knowledge nor technology to manufacture all thesubtle components ofa complete diet.

What should cooks know about water-soluble vitamins?

Unlike the four fat-soluble vitamins (A, D, E, and K), the eight Bvitamins and vitamin C dissolve in water. Though your body canstore the fat-soluble vitamins it needs in its fat cells for weeks,yourreserve of water-soluble vitamins is relatively short-lived. The primary reason is that the B complex and C vitamins easily flee ourbodies in our perspiration and urine. Consequently, you need toreplenish your supply of water-soluble vitamins on a daily basis.Here lies the wisdom ofdrinking a daily dose oforange juice (highin vitamin C) at breakfast and eating ample portions of vegetables(high in various B vitamins and sometimes in vitamin C) forlunch and dinner.

Because of their water solubility, the B complex and C vitaminsleave vegetables as easily as they do your body. One way to reducetheir loss is to cook your vegetables in as lillie liquid as possible inorder to minimize the quantity ofvitamins that leach out into thecooking medium. Steaming your food in a scant amount ofwater,therefore, is preferable to boiling it. And when you do steam (or ifyou must boil), use the leftover cooking liquid. Another vitamin'saving technique is to cook foods as quickly as possible, which iswhy Chinese woks are so highly touted by nutrition-consciouscooks.

health and nutrition . . 257

Are fresh vegetables more nutritious than frozen ones?

When referring to vegetables fresh from the farm, the answer is aresounding yes. However, a frozen-food product is likely to bemore nutritious than nonfrozen vegetables that have meanderedalong a time-consuming route from earth to palate. Typically, aslow truck transports vegetables from the farm to a warehouse,where they wait until they are shipped to the supermarket, wherethey wait until a customer takes them home to the refrigerator,where they wait again until the home cook decides to use them.When this journey is long and drawn out, as it usually is, the vegetables lose more vitamins than if they had been fast-frozen.

Under these circumstances, the product found in the supermarket's frozen-food section is often more nutritious because iffood processors are going to preserve their vegetables successfully,they must select ouly those that are the freshest and in the bestcondition, and they must normally freeze them within hours afterthey have been harvested, if not sooner. In addition, their freezingprocess is extremely cold and quick. (A shortcoming of freezing,ofcourse, is that it deteriorates texture.)

Is spinach more nutritious raw?

Though most vegetables are more nutritious when eaten raw,there are exceptions, and carrots and spinach are two. Many oftheir vitamins and minerals pass unused through the body because the human digestive system- unlike that of ruminant creatures-cannot sufficiently disintegrate the comparatively toughcellular walls of these vegetables and therefore cannot extract allthe nutrients.

Are most ofa potato's vitamins in the skin?

Vitamins in potatoes and most other vegetables are not concentrated in the skin (as some health food faddists believe), but in thepulp just under the skin. However, since it is impossible to peel apotato without scraping away some of the vitamin-rich pulp, it

health and nutrition . • 259

ated with coastal areas) or drink water that has acquired the mineral from such soil, you may be overdosing on iodine ifyou alsoregularly use iodized salt. The iodine-fortified product makesmore sense for people who live great distances from a seaboard.

What do alI the additives listed on a food package do?

The accompanying chart describes briefly the principal uses ofsome of the additives that are most frequently listed on packagesin supermarkets. Bear in mind that our list is far from comprehensive. The food industry uses hundreds of additives, too many toitemize in this book. We had to be selective.

Principal Use and Comments

Flavoring agent found naturally in manyfruits. Synthetic version is used in bakedgoods, beverages, chewing gum, gelatin,ice cream, liquor, and puddings.

Antioxidant that can also serve as a colorstabilizer and nutrient. Helps preservesuch foods as beer, bread dough, frozen

Additives Listed an Nutrition Labels

Ascorbic acid(vitamin C)

Additive

Acetic acid(ethyl acetate)

,Why does a candybar provide a quick energyboost?

Candy is rich in simple sugars that can be quickly digested and absorbed into your bloodstream, so you may feel an extra lift soonafter eating a candy bar. In contrast, your body must take the timeto convert more complex carbohydrates (such as are found in apotato or piece of bread) into glucose before they can be used forenergy.

On the negative side, a typical candy bar consists ofempty calories and does not provide your metabolism with valuable vitaminsand minerals. Nor does it furnish long-lasting energy; an hour orso after munching on the candy bar you may be hungry again orfeel a psychological and physical letdown because of the suddendrop in your blood sugar level.

What is an essential amino acid?

Amino acids are the building blocks of proteins that yourneeds to construct and replenish tissue, red blood cells, and enzymes. Ofsome twenty required amino acids, your body can manufacture all but eight of them. (Some authorities say nine.) Theseselect eight are called essential amino acids.

Proteins in meat have all eight essential amino acids andare referred to as complete protein. Vegetables, with the notableexception ofsoybeans, do not possess all the essential amino acids,and therefore their proteins are termed incomplete.

People who, for economic or personal reasons, eat scant quantities of meat, eggs, and dairy products and large portions ofwhole cereal grains are nutritionally safe, too, because animal protein has a surplus of the essential amino acids that cereal grainslack. This pairing partially explains why millions of people insouthern China can remain healthy on a diet consisting of a highproportion of rice (which, like other cereal grains, is particularlylow in the amino acid lysine) while usually eating no more than ameager serving ofseafood (high in lysine).

See chapter 15 (p.272) for a discussion ofhow vegans and traditional vegetarians obtain the eight essential amino acids.

makes sense to cook and serve it with its skin. Besides,the skin doeshave some nutrients and adds flavor, texture, and color contrast.


Which is better, iodized or plain salt?

Iodine is essential in the diet because without it, your thyroidgland could not manufacture thyroxine - a hormone necessaryfor bodily functions such as growth and the prevention of goiter.Because some Americans (particularly those in the so-called goiterbelt in the North Central states) suffer from iodine deficiency, theU.S. government encourages table salt processors to fortify theirproduct with potassium iodide to help ensure that everyone receivesenough of the mineral.

However, some medical authorities believe that ifyou eat aof seafood or food grown in iodine-rich soil (commonly


If the word"sugar" is absent from the ingredients list on a label,can the food still contain sugar?

Keep an eye out for the suffix"-ose," Dextrose, fructose, IaClOS,e,maltose, and sucrose, for instance, are all forms of sugar.are used as sweetening and sometimes preserving agents. Asplained in chapter 9, there is little nutritional difference amongthe various types of sugar- all provide empty calories. Whiletificial sweeteners such as sorbitol and saccharin have few, ifcalories, they also have no nutrients.

Sodium bisulfate,sulfur dioxide

Sodium chloride

Sodium nitrate,sodium nitrite

Sorbic acid,potassium sorbate

Sugar

Preservatives and antibrowningused in beverages, corn 'syrup, dehydrated potatoes, dried fruits, soups,and wine. Destroys vitamin B, (thiamine) in food.

Chemical name for salt, the world'snumber-one additive. Used to flavorand preserve a wide range ofprocessedfoods.

Preservatives and coloring agentsto inhibit the growth ofbotulisrn-producing bacteria. Can produce carcinogenic nitrosamines when combinedwith natural food substances calledamines. Found in most cured meats,including bacon, bologna, frankfurters, ham,salami, and sausages.

Naturally and synthetically produced.Prevents mold and, to some extent,bacterial growth in such foods asbaked goods, cheese, dried fruits,onnaise, soft drinks, syrup, and wine.

See next Q&A.

health and nutrition • • 263

Why does sugar cause tooth decay?

Sngar is food for plaque-residing bacteria colonies. They convertthe sugar into acid that corrodes tooth enamel, causing toothdecay. The degree of decay is dependent more on how long thesugar remains in contact with the bacteria colonies than on theamount of sugar consumed. For this reason, a pure caramel candyusually does less damage than a sugary cookie made with starch.The latter substance helps bind the sugar to the tooth.

Whydo I need fiber in my diet?

Fiber, also known as roughage or bulk, refers to the undigestiblecarbohydrates found in whole cereal grains, fruits, vegetables,seeds, legumes, and nuts. These undigestible substances facilitatedigestion and elimination by carrying other waste products alongwith them as they leave the digestive tract and by absorbing flnidsthat make wastes soft enough for easypassage.

Many doctors lay partial blame for various malfunctions anddiseases of the bowel, colon, and rectum on a deficiency of fiber inthe diet. Without adequate fiber, the intestines and bowel worksluggishly,and the wastes that result from the digestive process remain in your system longer than they should.

Fiber-conscious Americans and inhabitants of other countrieswhere highly refined foods glut the market usually must strive toconsume enough fiber. Unfortunately, some weight-consciouspeople do not consume enough fiber because they mistakeuly believe that carbohydrates per se are fattening. Dieters should also beaware that most fiber passes through the body without being absorbed, and according to medical evidence, it can help keep weightdown in two distinct ways. First, it is believed to help rid the digestive tract of some fats and carbohydrates that otherwise wouldeventually be absorbed into the body. Second, fiber's chewy texture and heaviness create a full feeling, making you less tempted tosatisfy yourselfwith refined high-calorie foods.

Too much fiber is bad, too. It can cause intestinal gas and hinder your body's ability to absorb certain minerals. How much is


too much fibers Some experts recommend a maximum of35 grams per day for the average adult male. .

What is the theory behind eating a varied diet?

Science has identified over 40 different essential nutrientsno one food ingredient offers them all. Moreover, bodv proba-bly needs some nutrients that food scientists know nothing ortle about. A diet rich in variety therefore stands a better chanceproviding all the necessary nutrients. A varied diet also lessenspossibility of consuming an unhealthy amount of any singletrient. Likewise, such a diet reduces the magnitude of exposureunwholesome substances such as toxins and pathogenic rnicroorganisms that any single food might harbor.

Why are fast eaters more prone to stomach~ches?

Food gobblers increase their chances of heartburn in two ways.First, they swallow a lot of air, Belching typically follows. Theing air sends acidic digestivejuices flying up to the esophagus. Second, since wolfers don't have time to chew their food intodigestible pieces, their stomachs are forced to release extradigestive juices to break down the abnormally large pieces.added acid can cause heartburn.

The type of food matters, too. Most chronic heartburn sufferersknow that high-acid foods can trigger the condition. So can alcohol and coffee-and lying down after a meal. It's not commonknowledge that fatty foods can also activate heartburn. Indirectly,they relax a valve in the esophagus that normally prevents theacidic gastric juices from backing up into the esophagus.

Some diners take antacid pills to relieve heartburn becausetheir alkaline ingredient helps neutralize the acid. One shoulduse this remedy on a steady basis, however, without seeking medical advice, because antacid pills alter the body's acid-base balance.

A frequently overlooked remedy is a glass of plain water. Itlutes the acid.

•lets

WE'VE INCLUDED this chapter because cooks playa major rolein determining the success of weight-reduction and other diets.Special diets are also discussed elsewhere, including in the cholesterol-related items in chapter 10.

Why do humans and other animals have fat?

The body's fuel is glucose (sugar). It is stored as glycogen (forquick energy) and fat (for longer-term needs). Converting glycogen into the needed glucose is a relatively fast process. Convertingfat into glucose, however, is considerably slower and more complex. Why, then, does the body need fat?Wouldn't it be simpler ifthe body used glycogen exclusively for its energy reserve? Glycogen has a shortcoming. It's a carbohydrate that, like protein,contains ouly four food calories (energy) per gram. Fat, in contrast, contains nine calories per gram. To substitute glycogen for 4pounds of fat, the body would need to carry around 9 pounds ofglycogen.That's an extra 5-pound burden.

What are the chances of regairIing the pounds you lose on a diet?

Unfortunately, the news isn't encouraging. Most people seeking tolose 10 or more pounds on a weight-loss diet will regain most or

265

Try This Taste BudMapping Experiment

potpourri • • 277

Map yourowntaste buds by placinginfront ofyoufourdean glasses,eachpartially filled with 1 ounce of roomtemperature waler.Add, and thoroughlystir, 1 tablespoon of sugar intothe first glass, 1 tablespoon of lemonjuice into the second glass, 1 teaspoonof salt into the third glass,and 2 teaspoonsof bitters, suchas the Angosturavariety, into the fourth glass.After tastingeach sample,note the place(s)where the specific flavors are the mostintense.

say that the umami taste may not be a basic taste. It could be, forinstance, a side effect of a chemical reaction triggered by glutamate, an amino acid (a building block of protein). When.glutamate is in its free form.(that is, not combined withother amino acids), it couldchemically modify the performance of the sweet, sour,salty, or bitter taste receptors,creating the illusion of a newbasic taste.

Whether umami is a basictaste or not, it is real and hasan identifiable flavor profile,though it is difficult to characterize in words. It has beenvariously described as "savory;' "brothv," and "meaty."These terms cover too broad a taste spectrum to communicate adequately the umami taste profile to anyone who does not alreadyknow it. Fortunately, monosodium glutamate is a salt form ofglutamate and does produce an umami taste. The experiment inchapter 9 (p. 181) will teach you how to identify the elusive MSGtriggered (and therefore umami) taste.

How do the sight, touch, and hearing senses influence our tasteperceptions?

Eaters sometimes erroneously ascribe the sensory perceptions ofsight, touch, and hearing to taste. As tests have proven, hamburgerthat has been dyed a bright green will not taste like hamburger tomost people. And if you could take the crispness out of a rawapple, most people would say, "It just doesn't taste right," ratherthancorrectly conclude, "It doesn't feel or sound right"

sour,salty,and sweet

Do taste buds exist beyond the top of the tongue?

Some of your 9,000 taste buds are also found on other parts ofyour mouth, including lips (usually very salt-sensitive), undersideof the tongue, and inner cheeks. The most overrated area is theroof of your mouth, your palate.


odor. That'swhy a smell of fish that is strong when you walk into arestaurant is usually low-keyed by the time you sit down at thetable.

Taste Bud Concentration Zones

on Topof the Tongue

bitter

low-intensity

What role do taste buds play?

Although the taste buds play second fiddle to the olfactory receptors in taste perception, they significantly affect how food tastes.Surprisingly,we sense an infinite variety of flavors through the interaction of just four primary types of taste buds-sweet, sour,salty, and bitter. Their intensity and location on the tongue varyfrom person to person.

Is umami the fifth taste?

Some taste physiologists argue that the basic-four list of tastes(sweet, sour, salty, and bitter) should be expanded to includeurnami (a Japanese term pronounced oo-mom-eei. Some laboratory research supports their view.

Other experts demur, believing that the jury is still out.

potpourri • . 279

Principle-Illustrating Recipe

MACADAMIA CHEESE SOUFFLE

4 servings

The basic souffle is no more than a thickened, flavored sauce (or pureeof meat, seafood, vegetable, or fruit) that has been lightened withbeaten egg whites and then baked. Once you learn the reasons whyyou follow certain procedures and avoid others, souffle making ischild's play-you'll end up with a glorious souffie each and every time.

'/. teaspoon salt'/. teaspoon black pepper

pinch of cayenne pepper

pinch of cinnamon

pinch of nutmegOptional: '/. teaspoon

cream of tartar

3 yolksof large eggs4 whites of large eggs3 tablespoons unsalted butter

5/. cup finely chopped or grated

Gruyere cheese3 tablespoons whitewheat flour

1 cup whole milk4 tablespoons finely chopped

macadamia nuts

1. Bring eggs and milk to room temperature.

Yoursouffle will rise to great heights only ifyou whip the egg whites totheir maximum volume-and to accomplish that goal, you must useroom-temperature, rather than cold,eggs.

2. Grease the inside of a 6-cup souffle dish with 1 teaspoon of the butterand then coat itwith 1 teaspoon of the cheese (shake out and discardany cheese particles that do not stick). Cover and chill the prepareddish i~ the refrigerator for 20 to 30 minutes. Preheat the oven to

400°F.Thoroughly grease the inside of the dish, and especially the side walls,because without the bufferlubricant, the souffle mixturewillstick to thedish and not rise freely. Chilling the dish keeps the bufferfrom meltingprematurely and sliding to the boffomduring baking.

3. Separate the eggs (all four whites in one bowl, three egg yolks in an

other).

Whydo makers ofquality pastaprefer semolina flour?

Semolina flour, which is made from part of the durum wheatberry, has a very high level of protein and cellulose, substancesthat help keep the cooked pasta relatively firm. Pasta madeother flours tends to become mushy when cooked. Semolina flouralso tastes better and is more nutritious thau its leading rivals.

What makes a souffle rise? What makes it fall?

Beaten egg whites make the souffle rise to the occasion of yourdinner party. They are also responsible for its downfall (the souffle's, not your dinner party's).

Egg whites (albumen), when beaten, consist of countless minute air bubbles. When the air inside them is heated in the oven, itexpands and enlarges the albumen bubbles, which in turn inflatethe entire souffle.When the air inside the bubbles cools, the souffle deflates.

The souffle also decreases in volume when a force such asmoving spatnla punctures some of the air bubbles. Thougha cook has blamed the collapse of a souffle on the spouse whoslammed the kitchen door, the force of the shock waves from thatdeed is too weak to pop more than a few air bubbles, if any atThe culpable party, if truth be told, is the cook who made onemore culinary errors in the science of souffle making. (For tipsmaking a successfulsouffle, see the recipe on the next page.)


Why does ice float?

Water has three phases: solid, liquid, and gas.In the solid phase,oxygen and hydrogen molecule components bind in a looser fashion, creating niches in the intermolecular crystalline structure.Liquid-phase water lacks these niches, so it's denser. Therefore, theliquid-phase water sinks, or, you could say with equal logic, theless dense ice floats.


3. Spices can also be varied, within reason, to suit your whims. Nevermake the same souffle twice-do at least one thing 'differently eachtime.

4. You can give your souffle a decorative dome. Using the end of awooden spoon or a finger, make a l/2-inch-cleep groove in your mixture, folloWing the circumjerenca of the dish, just before you place thesouffle in the oven. ill

Should cookbooks be stored in the kitchen?

It's a practical site, but if a cookbook is rare or irreplaceable, thekitchen is too hostile an environment. First, you run the risk ofthe book being attacked by mildew-causing fungi, which flourishin humid kitchens. Second, if your kitchen is lit with fluorescent lighting, the tubes may leak enough ultraviolet rays to causea damaging chemical reaction on the book's pages, cover, andbinding.

What is the most dangerous room in a home?

Hundreds of thousands ofaccidents OCcur annually in the American home kitchen. The cook has to contend with knives, hot surfaces, broken glass, faIling objects, slippery floors, and countlessdistractions, including children and spouses.

What is the bestway to treat a burn?

Ninety-nine percent of burns that occur in the kitchen are firstdegree burns and usually require only home treatment. A firstdegr~e burn is slightly red or discolored and causes only mildswelling and pain. If the burn is more severe than this, or ifit covers an extensive area of the body, call a doctor or emergency medical center.

The best way to treat a first -degree burn is to cool the burnedarea quickly by lightly pressing an ice cube against it. This stepminimizes the extent ofcellular damage.

Next, place several ice cubes in a clean plastic storage bag and

potpourri . • 283

gently apply it to the burned skin. As soon as the ice begins to feelunbearably cold, remove the bag. If the pain returns, place the icecube bag over the burned area. Keep repeating until the pain subsides (but not to the point where you risk frostbite).

If the burn covers a wide or hard-to-reach area, soak the partaffected in a suitable-size vessel or sink ofwater with plenty of icecubes.

The ice-cube treatment is superior to the old-fashioned rubwith-butter method because ice cubes numb the pain. Moreover,butter can foster infection.

Whichwillkeep food warm longer, a glass or metal serving dish?

Assuming that both containers are identical in size, shape, andthickness, the glass one will keep food warm longer. Glass is a considerably poorer conductor ofheat than is metal, and therefore therate of heat loss through the sides of the container is slower. Thesame principle is true for glass's close relative, ceramic.

Many other variables also affect heat retention, including thefood's fat and. moisture content. Fatty foods stay warm longer thanlean ones. Ditto for solid foods versus liquid ones like stews. Ofcourse, the most influential variable of all is whether the food iscovered.

Why is it more important to preheat a dinner plate than aserving dish?

The mass of the room-temperature (70°F) dinner plate is usuallymuch greater than that of the hot (say about 160°F) food. Consequently, an unheated plate will perceptibly cool the food before allof it has had a fair chance to be eaten and enjoyed. The cooling effect is almost as acute for a serving platter.

A deep-sided serving dish for a stew, soup, or vegetable posesless of a problem. The quantity of the heated food will usuallywarm the serving dishbefore the dish can appreciably cool the hotfood.

potpourri • • 285

Glue-removingproducts areformulated toloosen chemically the bondsbetween theglue and themetal pot


How does soap help clean a dirty dish?

Soap (and detergent) reduces the relativelyhigh surface tension ofwater and so enables the water molecules to penetrate better thepores of the food residue clinging to the dish. Unless that happens,some of the food particles-although surrounded by a sinkful ofwater-can remain dry, hard, and difficult to remove.

Soap helps clean dirty dishes in another way. Oil and water molecules naturally repel each other, and thus the water alone cannot effectively penetrate oil, or oil-coated food, on the dish. However, with the aid of an emulsifying agent like soap or detergent,the water and oil will mix and travel down the drain together.

A soap molecule is an emulsifier because of its split personality.One of its two ends is hydrophilic: It is drawn to water and shunsoil. The other end behaves in the opposite manner, It is hydrophobic-repulsed by water and attr~cted to oil. The soap molecule'shydrophilic end binds itself to the water, while the hydrophobicend attaches itself to the oil-,A little elbow grease on your part, andthe oil molecule glides off the plate. The oil-soap-water emulsionis not, however,permanent-as you can tell from the oil layer thatsometimes lightly coats your hands.

In addition to its molecular properties, soap makes the watermore viscous by its sheer physical presence. This increase allowsthe fluid to carry more and larger particles, so that freed soil floating in even relatively dirty water usually is not forced to take upresidence on a soaking plate once again.

Why is hot water a better dish-cleaning medium than coldwater?

Not ouly does hot water make oil and other food substances morefluid and therefore easier to dislodge, but it also has a lower surface tension than cold water. The hot water therefore better penetrates the food, and just as important, the soap or detergent canmore readily form an oil-and-water emulsion. When cleaning adish smeared with a raw or cooked flour paste, however, do notmake the water too hot, lest the flour become instant glue.

Why is flour so difficult to remove from pots and utensils?

Flour is a starch and therefore can be quite sticky when exposed towater. Adhesive makers know this principle well: Starch is thebasic material for many of their products.

Always rinse or soak a flour-coated pan or implement immediately after you use it. Use lukewarm water rather than hot, becausetemperatures higher than 140°F tend to cook flour, thereby increasing the adhesiveness ofa flour paste.

Howdo I rid the inside .0£my teakettle ofits deposit buildup?

Ifyou have been boiling only water inside your kettle, the hard deposit layer is mainly alkali compounds and minerals. Acid can dissolve such deposits. Fill the teakettle with a mixture of one partvinegar to six parts water, and let it stand overnight The next daythoroughly wash out the .kettle, If necessary, you can repeat the

process.In contrast, stains caused by acids like tea or coffee are best re

moved with an alkali such as baking soda.

Howcan I remove a glued label from a new metalpot thoroughly and easily?

The soak-in-water method doesn't work wellon most modern label glues. Solution: Glueremoving products are formulated to loosenchemically the bonds between the glue and themetal pot. Youhave another option ifthe label ison the outside of a pot-use heat. Fill the potwith boiling water and let it stand. In most cases, the heat willloosen the glue's hold on the metal. Be patient. Don't try to peel alabel off the pot prematurely lest hard-to-remove remnants of theglue remain bonded to rpe metal instead ofthe label.

How do I separate stuck-together glasses?

The two glassesshould part ifyou contract the inner glass and expand the outer glass by subjecting them to cold and hot tempera-

Food Science (Scan)

Documents

Transcript of Food Science (Scan)