Storage of Milk Products

Refrigerated

All fluid milk except unopened, aseptic packs of ultrahigh-temperature pasteurized milk and certain canned milk products should be stored in the refrigerator. They need to removed only long enough to take what is to be used and then quickly returned to the refrigerator. Read more »

Whipped Milk Products

Liquid milk products such as cream, evaporated milk, and reconstituted nonfat dried milk can be made into a foam by whipping air into the liquid. During whipping, the protein in these milk products is mechanically stretched into thin layers that trap air bubbles, fat particles, and liquid. Read more »

Enzymes in Milk

Milk also coagulates and forms curds when it combined with certain enzymes originating from animal, plant, or microbial sources. Enzymes used to coagulate milk include pepsin from the stomach of swine, proteases from fungal sources, and certain enzymes from fruits. Read more »

Adding acid to milk causes the casein in the milk to coagulate. Casein precipitates when the normal 6.6 pH of fresh milk drops below 4.6. Whey proteins do not coagulate. Sources of acids include those from foods such as lemon and lime juices, tomato products, and certain fruits; or from bacteria-produced acids in cultured milk products. Read more »

Heating Milk

When milk is heated to near the boiling point, the whey proteins lactalbumin and lactoglobulin become insoluble, mesh with the milk’s calcium phosphate, and precipitate, forming a film on the bottom and sides of the pan. This film can scorch easily. Scorching can be prevented by constant stirring, slow temperature increases, or use of a double boiler. Read more »

The bland, slightly sweet flavor of milk comes from its lactose, salts, sulfur compounds, and short-chain fatty acids. The percentage of fat determines the mouthfeel and body of a particular milk. Read more »

About Cream

Cream is a collection of fat droplets that float to the top of nonhomogenized whole milk. The heavier and thicker the cram, the higher the fat content. Cooling the cream firms its fat globules and makes it even thicker. Read more »

Sour Cream

Cream can be soured by Streptococcus lactis bacteria or some other acidifying agent. Light cream or half-and-half is fermented at 72^oF (22^oC) until the acidity from lactic acid reaches 0.5 percent. A thicker sour cream is produced if milk solids-not-fat (MSNF), vegetable gums (carrageenan), or certain enzymes are added. To be labeled sour cream, a minimum of 18 percent milk fat is required, although when sweeteners are added, the minimum milk fat content can be lowered to 14.4 percent. Lower-fat sour creams with half the fat content of standard sour cream, and sour cream substitutes, are also available.

Acidophilus Milk

Acidophilus milk is a cultured milk created with the assistance of Lactobacillus acidophilus. These bacteria break down lactose to glucose and galactose, resulting in twice as many sugar molecules. The resultingly somewhat sweeter milk, usually packaged in cartons, is made by inoculating pasteurized milk with L. acidophilus culture and letting it incubate at 99^oF (37^oC) until a slight curd forms. Read more »

About Buttermilk

Buttermilk contains little or no butterfat. Sweet natural buttermilk originally was the liquid left over after fresh cream had been chilled and churned to produce butter. Natural buttermilk is often dried and used in baked products and ice cream, because the phospholipids obtained from the fat-droplet membranes, which are broken down during churning, makes it an excellent emulsifier. Read more »