Milk and Milk products are a nutritious food for humans, but it also provides a favourable environment for the growth of microorganisms. Yeasts, molds, and a broad spectrum of bacteria can grow in milk, particularly in a range of temperatures between 6-60 degrees Celsius. Microbes can enter milk via the cattle, air, feedstuffs, milk handling equipment, and the milker. Once microorganisms get into the milk, their numbers can increase rapidly and may cause spoilage or chemical change in the product.