Preservation of Food

Deterioration of food is caused by the growth of micro-
organisms (bacteria, yeast and molds) and by enzymatic action.

Enzymes can cause such changes in food as loss of flavor
and discoloration. Enzymes are destroyed by heating — their action
is retarded by low temperatures.

Yeasts and molds are readily killed by heat but bacteria
is more difficult to destroy because some types are more heat
resistant than others.

Decomposition of food is checked or retarded by applying
one of the following methods of food preservation. Sometimes two
or more methods are used in combination.

a.
b.
eg.
da.
e.

Low temperatures (refrigeration and freezing)

High temperatures (canning)

Drying

Excluding air

Adding preservatives (sugar, spices, vinegar, salt, smoking)

Canning is a method of using high temperatures and air-
tight containers to preserve food.

One of the first rules for successful canning is the selec-
tion of top-quality fresh food.

Jars and caps play a very important part. Only standard
jars made for canning should be used.

It is very important to process food for the full period rec-
ommended inthe time table. No matter how carefully food may have
been chosen and prepared, if not processed long enough it will
spoil.

Preparation and Types of Jars

Inspection and Preparation of Jars Before Using

Test all jars by checking forcracks and feeling rims. There