Give 5 method for food preservation.

a) Chemical method of preservation is done by adding certain chemicals which have the capability of preserving the food. Preservatives include sodium benzoate and sodium metabisulphite used in jams and squashes. 
b) Preservation by vinegar is done by adding vinegar as microorganisms cannot live in sour environment provided by the same.
c) Preservation by sugar is done by adding sugar which reduces moisture in food. It also inhibits the growth of microbes that spoil food. Jams, jellies and squashes are preserved using sugar.
d) Preservation by oil is done by adding oil, as bacteria and fungi cannot live in an environment provided by oil.
e) Sun drying is one another method of preserving food. Food like vegetables and fruits are sliced and sundried in order to remove moisture from them. These dehydrated food products can be stored and preserved.
f) Salting is done by using common salt. Sodium chloride used as common salt absorbs moisture from food, making it dry and uninhabitable for microbes.