Milk • Most comes from cows and has a layer of cream on top. • Can be homogenised by forcing milk through tiny holes under great pressure ,so the fat globules break down and cannot reform • Deteriorates quickly so its heat treated to extend its shelf life and kill bacteria. • All milk products unless dried and canned should be stored in the fridge.
Primary processing of milk Pasteurised • When milk is heated to 72C for 15 seconds and cooled rapidly to 10C or below • Skimmed milk is pasteurised with all the cream removed • Semi skimmed milk is pasteurised with some of the cream removed. • UHT milk is heated to 132-140C for 1 second before being cooled rapidly.
Primary processing of milk • Sterilised milk is homogenised, bottled, sealed and heated to 110C for 30minutes which alters the taste. • Dried milk is less bulky to store and keeps without needing to be refrigerated.
Primary processing of milk • There are two types of canned milk • In evaporated milk, water is evaporated making the milk more concentrated and sweeter. It is homogenised and sealed in cans then sterilised. • Condensed milk is evaporated milk that is not sterilised. Extra sugar is added making it thick and sweet.
Lactose intolerance • People with lactose intolerance can substitute cows, sheep and goats milk in their diets with • Soya milk • Rice milk • Coconut milk • Oats milk • All these types do not contain lactose.
Secondary processing of milk Butter • Is made by churning cream. • Types of butter are salted, unsalted, clarified and ghee. • Butter may be added to some margarines to improve their flavour.
Secondary processing of milk Cream • Is made from the fat of the milk. • Types of cream are single, whipping, double, and extra thick cream. • Cream can be further processed to make creme fraiche, clotted cream and soured cream.
Secondary processing of milk Cheese • Is milk in a solid form. It is one third each of protein, fat and water. • Many different cheeses are available, and are different because of the way they are made. • When cheese is heated the fat melts and separates, the protein coagulates and shrinks making the cheese harder to digest.
Secondary processing of milk Yoghurt • Is made by adding a bacterial culture to milk. • Probiotic products contain billions of live bacteria which benefit the digestive system.