Food Production:How are Food Preserved?

Prepared by:

Joel P. Ogoc, Ed. D.

Master Teacher II

Science Department

ZNNHS

Food is a precious commodity

As such, people are looking for ways to prevent food spoilage

Food spoils due to microbial actions of microorganisms like molds, yeast and bacteria

Microorganisms secrete enzymes that break down food into simpler substances

Such microbial actions are accompanied by undesirable food changes like

Bad odor

Unpleasant taste

Color and texture change

These changes are signs of decay

To prevent these undesirable changes, people apply food preservation techniques

Drying

This method is based on the following principles

Microorganisms cannot live without water

Action of microbial enzymes on food require water

Enzymes convert food molecules to simpler forms

Cellular respiration only occur on simpler forms of food molecules

Thus food do not easily spoil when kept dry

This is the most convenient way preserving food

Palay and corn grains are usually dried before storage

Copra and peanuts are dried to prevent aflatoxin

Meat and fish are salted and dried

Refrigeration

This method is based on the following principles

Digestion of food requires digestive enzymes

Digestive enzymes requires a warm temperature

Refrigerators have low temperature

Putting food in the ref slows down action of digestive enzymes

Another thing is

Cold temperature in the ref slows down action of microbial enzymes

These enzymes are needed in respiration and fermentation

Thus refrigeration inhibits respiration and fermentation

This is the reason why fruits, vegetables and meat are kept fresh inside the ref

Fermentation

This method is based on the following principles

Salt is added to the food

The salt removes the water from the cells

Most microorganisms cannot survive in the resulting salt solution

But lactic acid bacteria can live in salt solution

These bacteria ferments the food forming lactic acid

Lactic acid controls the growth of decay microorganisms

Common products of lactic acid fermentation are cheese and bagoong

As well as burong mangga, burong hipon, burong isda, burong talangka and burong mustasa

Another application of fermentation uses yeasts to produce alcohol and carbon dioxide

Juices are preserved this way where yeast acts on the sugars of the juice and changes it to alcohol

Common products of alcoholic fermentation are wine, beer and other alcoholic drinks

Yeast also makes bread light and fluffy

Mixing yeast with the dough makes it rise due to the formation of carbon dioxide

Before yeast was used in baking, bread was flat and hard

Can you think of other food preservation techniques?

Make a brochure about this technique which will include the following:

Its definition

The principle behind it

Step by step procedure of doing it

Popular products of this method with pictures if possible