Causes of spoilage of food:

I. Physical and mechanical damage: By equipment during harvesting, falling fruits to the land

II. Spoilage by microorganisms: By bacteria, yeasts, molds etc

III. Spoilage by enzymatic reaction:

a) Senescence and decay: In case of fruits and vegetables

b) Outolytic changes of raw fish and meat

c) Sprouting of grains

IV. Spoilage by rodents, pests, insects, birds etc

V. Spoilage by purely chemical reaction

VI. Faulty preparation and processing

Aims of commercial food preservation

I. To preserve food in transits from producer to consumer by preventing undesirable changes in wholesomeness, nutritive value or sensory quality by economical method which control microbial growth, reduce physical, chemical and physiological changes and also reduce contamination

II. To smooth out irregularities in production, especially to overcome the hardship of season

III. To ensure as per as possible that local or seasonal surpluses are not wasted

IV. To facilitate handling which is done primarily through various forms of packaging