Food Preservation and Storage

Food Preservation Storage

Lesson 04: Principles and Methods of Food Preservation

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. Food preservation operates according to three principles, namely:

Prevention or delay of microbial decomposition brought out by

1. Keeping out microorganisms or asepsis
2. Removal of microorganisms e.g. washing, filtration etc.
3. Hindering the growth and activity of microorganisms by controlling the conditions required for the growth and activity of microorganisms by use of low temperature, drying, maintenance of anaerobic conditions or chemicals
4. Killing microorganisms by heat or irradiation

Prevention or delay of self-decomposition of foods by

1. Destroying or inactivating food enzymes e.g. blanching, low temperature storage, chemical preservation, drying etc.
2. Preventing or delay of chemical reactions e.g. prevention of oxidation with the use of antioxidants as oxygen speeds up decomposition of food and antioxidants deprives food from oxygen.

• Prevention of damage because of external factors such as insects, rodents, dust, odour, fumes, and mechanical, fire, heat or water damage.
  Eg. Use of boxes, cartons, and shock absorbing materials, sealed tight, vacuum-packaging etc.