Beneficial Bacteria

Bacteria aren’t all bad… their just misunderstood.

Bacteria in Food• Most people think

bacteria in food can only be harmful.

Bacteria in Food• However,

certain bacteria are safe in food, and are required for the desired taste and texture.

Fermented Foods: Ancient Traditions

• Fermentation is one of the oldest forms of food preservation technologies in the world.

Fermented Foods: Ancient Traditions

• Fermentation – biochemical change caused by anaerobic oxidation of carbohydrates by microorganisms or by enzymes.

• tempeh

Fermented Foods: Ancient Traditions

• Fermented drinks – 7000 years ago in Babylon (now Iraq).

Fermented Foods: Ancient Traditions

• Bread-making – 3500 years ago in Egypt.

Fermented Foods: Ancient Traditions

• Soy sauce – over one billion liters is produced each year in Japan alone.

Fermented Foods: Ancient Traditions

• Fermented cassava products – major component of African diet, 50% for some.

Which foods?• Bacteria are

commonly used in dairy products.

Which foods?• Sour cream and

Crème fresh are both the product of cream after bacteria were allowed to grow in it.

Which foods?• The difference in

flavor, texture, and behavior (only sour cream curdles when heated) all result from the differences in bacteria required to produce the two products.

Which foods?• Buttermilk is low

in fat; cheese comes in many varieties so there are many types of microorganisms used.

Which foods?• Yogurt is

probably one of the oldest forms of fermented milk.

Which foods?

•It may be beneficial to eat diary products with living bacterial cultures.

Which foods?• Vegetables can

be fermented too.

Which foods?• Sauerkraut is

made of finely cut white cabbage leaves and salt.

Which foods?• Lactic acid

bacteria make it taste sour; the salt stops “bad” bacteria from growing.

Which foods?• Olives and

pickles are fermented in brine.

Species Function ProductPropionibacterium shermanii

Flavor and eye formation

Swiss cheese family

Lactobacillus bugaricusLactobacillus lactisLactobacillus helveticus

Acid and flavor Bulgarian buttermilk, yogurt, kefir, koumiss, Swiss, Emmental, and Italian cheeses

Lactobacillus acidophilus Acid Acidophilus buttermilk

Streptococcus thermophilus

Acid Emmental, Cheddar, and Italian cheeses, and yogurt

Streptococcus diacetilactis

Acid Sour cream, ripe cream, butter, cheese, buttermilk, and starter cultures

Streptococcus lactisStreptococcus cremoris

Acid Cultured buttermilk, sour cream, cottage cheese, all types of foreign and domestic cheeses, and starter cultures

Streptococcus durans Acid and flavor Soft Italian, Cheddar, and some Swiss cheeses

Leuconostoc citrovorumLeuconostoc dextranicum

Flavor Cultured buttermilk, sour cream, cottage cheese, ripened cream, butter, and starter cultures.

What else do good bacteria do?

• Nitrogen fixing – all organisms need nitrogen, there’s lots in the air, but few organisms can “use” it.

What else do good bacteria do?

• Decay – think of the piles of dead organisms and poop that would be lying around… yuck.

What else do good bacteria do?

• Aid in digestion – found in many digestive tracts of different animals… even humans.

What else do good bacteria do?

• Activia – brand of yogurt that contains live bacterial cultures.

What else do good bacteria do?

• Prevent growth of “bad” microorganisms… after taking antibiotics, some babies get diaper rash