Milk products

Milk is known to be widely used not only in the fresh fluid form, but in some concentrated and preserved forms. It is important that concentrated and dried milk products occupy less space, weigh less, and remain edible longer than fresh milk.

Concentrated milks. This term refers to those products from which sufficient water is removed to concentrate the milk fat to at least 7.5 Percent and total milk solids to at least 25.5 percent.

Whole, low-fat and skim milks, as well as whey and other dairy liquids, can be efficiently concentrated using heat under vacuum. Since reducing atmospheric pressure lowers the temperature at which liquids boil, the water in milk is evaporated without affecting a cooked flavour. There exist more modern expensive technologies such as ultra filtration. Concentrated milk is pasteurized but not sterilized by heat to prevent spoilage, and then preserved by refrigeration. The obtained product is sure to require less storage space, so it costs less to distribute.

Condensed milk. This term is usually applied to the product obtained by partially removing water from a mixture of milk and suitable nutritive sweetener. The final product contains about 8.5 percent milk fat and at least 28 percent total milk solids. Being added in sufficient amounts (at least 60 % in the water phase), sugar provides high osmotic pressure and prevents bacterial action and product spoilage, thus facilitating the storage of the product at room temperature! It is interesting that sweetened condensed milk was first produced on a commercial scale in about 1858 in New York, and today it is often sold in refrigerated tank-truck loads' to manufacturers of candy, bakery goods, ice cream, cheese, and other foods.

Evaporated milk. The name is reserved for the product made from homogenized milk by concentrating with heat and vacuum to obtain at least 25.5 percent total milk solids and 7.5 percent milk fat, and by further sterilizing of the product in the sealed can2 at 118°C. It is essential to fortify the product with vitamins A and D. A stabilizer, such as disodium phosphate, is also added to keep the product from separating during processing and storage. To obtain high-quality evaporated milk, new ultrahigh-temperature processing as well as aseptic filling of metal cans are widely practiced. These measures prevent evaporated milk from caramelized flavour and allow to store it for several months at room temperature.