Milk and Milk-Product Microbiology
Milk is considered to be the ‘most nearly perfect’ food for man and hence is one of the most important articles of the diet. It is an extremely complex mixture and usually contains about 87% liquid (water) and about 13% solid. Of the solids, there is an average of about 4% fat and 9% solids other than fat. The latter consists of protein (about 3.3%) lactose (about 5%) and the ash content about 0.7%. The protein includes casein and albumen. There is usually about four times as much casein as all the other protein constituents of milk taken together. In addition to these, there are hydrolytic enzymes too. Milk serves as an excellent medium for the growth of many bacteria and is contaminated from various sources. Microorganisms play an important role in dairy industry. The quality and conditions of production of milk can be judged by microbial contents.