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 Classification of Foods based on stability: Food is anything eatable that will provide carbohydrate, protein, fat, minerals, vitamins for energy metabolism, body mass production and normal function of the body parts respectively.Foods can be classified into three groups depending on how long they can be kept without any treatment.  Perishable foods : Foods that spoil readily unless special preservative methods are used. E.g. milk, eggs, meat, fish, poultry, most fruits and vegetables.   Protectable or semi-perishable foods : Foods those remain unspoiled for a fairly long period if properly handled and stored. E.g. potatoes, apples, onions etc. Relatively stable or non-perishable foods : Foods that do not spoil unless handled carefully. E.g. grains, flour, sugar, pulses etc. A.Perishable foods:   Perishable foods can be kept at room temperature for only few hours or 1 or 2 days before spoiling.  For example- milk and milk products, meat, fish, poultry, fruits, l...

 Food spoilage: b. Sources of food spoilage micro-organisms Food spoilage : According to the Oxford English Dictionary to spoil is to ‘ deprive of  good or effective qualities ’. When a food is spoiled its characteristics are changed so that it is no longer acceptable . Such changes may not always be microbiological in origin; a product may become unacceptable as a result of insect damage, drying out, discolouration, staling or rancidity for instance, but by and large most food spoilage is a result of microbial activity . Microbiological food spoilage can manifest itself in several different ways, some of which often occur in combination . Visible microbial growth may be apparent in the form of surface slime or colonies, degradation of structural components of the food can cause a loss of texture, but the most common manifestation will be chemical products of microbial metabolism, gas, pigments, polysaccharides, offodours and flavours . Food spoilage can be defined...