Preservatives—Those chemicals which prevent undesirable changes in flavour, colour, texture, appetitic appeal during a storage are called preservative. They delay these changes and prevent spoilage of food due to microvial growth. The most common preservative is sodium benzoate(C6H5COONa) .
Class 1 preservatives-includes table salts, sugar , vegetable oil.
Class 2 preservative—sodium benzoate ,salts of sorbic acids and propanoic acid.