Show the Principles of preservation?

Various methods can be used for preservation of foods like freezing, pasteurization, sterilization, canning, dehydration, use of preservatives and preservation by high osmotic pressure.

All these techniques of food preservation involve the following principles of preservation:

1) Prevention or delay of microbial decomposition.

a) By keeping out microorganisms (asepsis).

b) By removal of microorganisms e.g. by filtration.

c) By hindering the growth and activity of microorganisms e.g. by low temperature, drying, use of chemicals.

d) By killing microorganisms e.g. by heat, radiations.

2) Prevention or delay of self-decomposition of food

a) By destruction or inactivation of food enzymes e.g. by blanching.

b) By delay of chemical reactions e.g. use of antioxidant to prevent oxidation.

3) Prevention of damage caused by insects, animals and mechanical damage by rodents etc.