The Different Types of Milk

About half the milk produced in the United States is sold as fluid milk and cream. Much of the rest comes to the market as butter, cheese, and ice cream. The available market forms of milk include fluid milk - whole, reduced fat (2 percent), low fat (1 percent), fat-free (non fat), UHT, chocolate, and many others like dry milk, cream, and cultured milk products such as yogurt and buttermilk. Read more »

Homogenization of Milk

Fat is less dense than water, causing it to float to the top of milk. This results in the thick layer of yellowish cream that rises to the top of unprocessed milk. Homogenization prevents this separation of water and fat. The mechanical process of homogenization pumps the milk under a high pressure of 2,000 to 2,500 pounds per square inch through fine holes, which breaks up the fat globules. This decreases the fat globule size to less than 2 microns. Read more »

Pasteurization of Milk

Milk is an excellent growth medium for microorganisms such as bacteria, yeast, and molds. In the early 1900s, it was frequently the vehicle for carrying such serious foodborne illnesses as typhoid, diphtheria, scarlet fever, and tuberculosis. Pasteurization, named after Louis Pasteur (1822-1895), was originally used to treat wine and beer, but soon came into use to treat milk as well, when it was found that heating milk for a short time to below its boiling point killed microorganisms. Read more »

Vitamins in Milk

Milk contains vitamins A and D, riboflavin (B₂) and tryptophan, an amino acid important in the formation of the B vitamin niacin. It is low in vitamins C and E. Milk exposed to ultra-violet light loses riboflavin, so it is packaged in cardboard or opaque plastic containers to prevent the degradation of this vitamin by light. Read more »

The fat in milk, called milk fat or butterfat, plays a major role in the flavor, mouthfeel, and stability of milk products. The creaminess of milk chocolate, for example, is due to the milk fat, which softens the characteristic brittleness of cocoa butter. Milk fat consists of triglycerides surrounded by phospholipid-protein membranes (lipo-proteins), which allow them to be dispersed in the fluid portion of milk, which is primarily water. Read more »

Carbohydrate in Milk

Lactose, or milk sugar, is the primary carbohydrate found in milk - 12 grams per 8-ounce cup. When bacteria in milk metabolize lactose, lactic acid is produced. The flavor of cheese and fermented milk products such as yogurt and sour cream is, in part, derived from the lactic acid. Read more »

Composition of Milk

People have been using milk as a food source for thousands of years. Records from ancient Babylon, Egypt, and India show evidence of cattle being raised for their milk. Milk is a unique beverage that provides complete protein, many of the B vitamins, vitamins A and D, and calcium. Read more »

Antioxidants, natural and commercial, are added to foods containing large amounts of unsaturated fats in order to prevent rancidity. The USDA’s Code of Federal Regulations defines antioxidants as substances used to preserve food by retarding deterioration, rancidity, or discoloration due to oxidation. Read more »

Preventing Rancidity

In the past, cereal manufacturers incorporated predominantly saturated fatty acids such as coconut and palm oils into their products to reduce the risk of rancidity. Public concern over saturated fat and its relationship to blood cholesterol levels has contributed to increasing use of unsaturated oils and new ways of deterring rancidity. Read more »

The different types of rancidity

There are two basic types of rancidity: hydrolytic rancidity, which occurs when water breaks larger compounds into smaller ones; and oxidative rancidity, in which the double bond of an unsaturated fatty acid reacts chemically with oxygen to result in two or more shorter molecules. Read more »