List out the Principles of Food Preservation?

All food preservation methods are based upon the general principle of preventing or retarding the causes of spoilage caused by microbial decomposition, enzymatic and non-enzymatic reaction, chemical or oxidative reactions and damage from mechanical causes, insects and rodents etc. The basic principles of the different preservation methods are given in Table.

Table: Principles of food preservation

A.  Prevention or delay of microbial decomposition:

• By keeping out microorganisms (asepsis) 
• By removal of microorganisms e.g. by filtration. 
• By hindering the growth and activity of microorganisms e.g. by low temperatures, drying, anaerobic conditions or chemicals. 
• By killing the microorganisms e.g. by heat or radiations. 

B. Prevention or delay of self-decomposition of the food:

• By destruction or inactivation of food enzymes e.g. by blanching. 
• By prevention or delay of chemical reactions e.g. prevention of oxidation by means of an antioxidant. 

C. Prevention of damage because insects, animals and mechanical causes.