Food spoilage is defined as decomposition and damage caused to food by
various agents making it unfit for consumption.
‘Spoilt’ is the term used for foods which look harmful and unfit to eat.
Spoilt food has an unattractive colour, smell, taste and appearance.
The term ‘contamination’ means
foods which are not fit to be eaten for san-itary reasons. The foods may look
good, and taste and smell good, but may contain harmful chemicals, non –food
matter and bacteria.
Foods may be contaminated by air,
water, plant, soil, food handler, machinery and equipment, sewage and trucks or
carts during transport. Foods get spoilt due to any one or more of the
– damage like cuts,bruises
– like the enzymes in the food
Biological–changes brought about by the
microorganisms and their enzymes.
Physical spoilage is caused by improper temperature, compact stacking which
leads to change in the structure of the food.
The changes are brought about by enzymes present in food (intrin-sic)
or those produced by microorganisms (extrinsic) are of different kinds.
enzymes destroy vitamin C and produce deterioration in flavour.
Proteolytic enzymes produce decom-position of
proteins like meat,fish,eggs and milk.
Amylolytic enzymes hydrolyse carbo-hydrates.
Lipolytic enzymes produce a break-down of fats into
fatty acids and glycerol that are often oxidized to per-oxides and aldehydes
associated with rancidity or a bitter taste in fatty foods.
c. Biological: Biological factors that spoil food are the microorganisms like
moulds, yeasts bacteria and their en-zymes which settle in food at different
stages. The changes brought about in the food are mainly in the form of
fermen-tation, putrefaction and decay.
i. Fermentation: It is the anaerobic
enzymatic conversion of carbohydrates into
ethyl alcohol. It
is caused by Streptococcus and Micrococcus.
ii. Putrefaction: It is the enzymatic de-composition of the proteins present in food with the production of foul smelling compounds such as hydrogen sulphide and ammonia. It is caused by Pseudomonas and Proteus.