FOOD PRESERVATION

COOLING

• REFRIGERATION-food is maintained at temperatures only a few degrees above 0ºc

• FREEZING-the food i store between 0ºc and-18ºc

• DEEP FREEZING-the food is kept between -35ºc and -150ºc

HEATING

• STERILISATION-the food is subjected to temperatures between 110ºc and 120ºc

• UHT(ULTRA HIGH TEMPERATURE)-the food is heated to a very high temperature(135ºc)for a few seconds

• PATEURISATION-a temperature os about 72ºc is applied for 15 seconds,and then the food is rapidly cooled down

DRYING

• This process involves eliminating the water in food to stop or delay decomposition.

• FREEZE-DRYING is a common method:the food is frozen,and then dried in a vacuum to eliminate the water by sublimation

VACUUM PACKING

• This removes the air(and therefore,the oxygen)from food,so that aerobic microorganisms cannot survive and many enzyme reactions connot take place

IRRADIATION

• Certain food products are subjected to radiation.this destroys the enzymes and the microorganisms

FERMENTATION

• Some food can change because of the action of specific microorganisms through fermentation.In some cases this not only makes the food last longer,it also gives the food new nutritional qualities

SMOKING(aumado)

• The smoke from burning wood contains substances that kill microorganisms.Also,the loss of water that occurs during smoking helps stop food from deteriorating

USE OF PRESERVATIVES

• Large quantities of sugar or salt can help preserve food by killing microorganisms.Jams and conserves are examples of foods preserved with sugar

• Vinegar and spices are also good for preserving food