1. A secretion of the mammary glands for the nourishment of the young.

Milk from cows consists of water, organic substances, and mineral salts. Organic substances: Proteins: The principal proteins are caseinogen, lactoalbumin, and lactoglobulin; in the presence of calcium ions, soluble caseinogen is converted into insoluble casein by the action of acids, rennet, or pepsin. This brings about the curdling of milk. Lactoglobulin is identical with serum globulin of the blood and hence contains maternal antibodies. Carbohydrates: Lactose (milk sugar) is the principal sugar, although small quantities of other sugars are present. Fats: The principal fats are glycerides of oleic, palmitic, and myristic acids. Smaller quantities of stearic acid and short-chain fatty acids with carbon chains of C4 to C24 are present. Sterols and phosphatides (lecithin and cephalin) are also present. Churning causes the fat globules to unite into a solid mass and separate from the whey to form butter. Mineral salts: The principal cations are calcium, potassium, and sodium; the principal anions are phosphate and chloride. Citrates and lactates are present in small quantities. Milk is low in iron and magnesium.

Vitamins: Vitamin A and those of the B complex (thiamine, riboflavin, and pantothenic acid) are present in adequate quantities to meet the needs of a growing child. Milk is low in vitamins C and D.

Milk contains antibodies that are present in the mother's blood and a number of enzymes (catalase, oxidase, reductase, phosphatase).

acidophilus milk

Milk inoculated with Lactobacillus acidophilus, a bacterium that grows best in an acid medium. It is a probiotic food, used to modify the bacterial flora of the digestive tract.
2. A white substance secreted by plants, e.g., the liquid from milkweed or that may be processed for use as a milk substitute for humans, e.g., soy milk or almond milk.

breast milk

Milk obtained from the mammary glands of the human breast. It is the ideal source of nutrition for most infants, since it contains maternal antibodies that protect the child from infection, and other substances that promote development of the brain and the gastrointestinal tract, among other organs. Human breast milk that is collected and refrigerated immediately may be used for up to 5 days. If it is collected, frozen, and stored at −17.7°C (0°F), it is safe for 6 months.
Descriptive text is not available for this imageBreast-feeding by mothers with human immunodeficiency virus (HIV) is not recommended, because of the risk of transmission of HIV to the child.

Bulgarian milk

Milk fermented with Lactobacillus bulgaricus.

butter milk

SEE: buttermilk.

casein milk

Milk prepared with a large quantity of casein and fat but little sugar and salt, e.g., a product like whole fat milk.

condensed milk

Milk from which water has been removed and sugar has been added to make it thick and sweet. It is an ingredient in dessert recipes.

cow's milk

Milk obtained from cows.

donor milk

SEE: Pasteurized donor breast milk.

evaporated milk

Cow's milk concentrated by the evaporation of some of the water. It can be canned after pasteurization and stored for a long time.
SEE: lactic acid evaporated milk

fermented milk

Any cultured dairy product, such as buttermilk, cheese, kefir, koumiss, and yogurt.
SYN: SEE: fermented dairy product
SEE: koumiss

fore milk

Milk released at the beginning of each breast-feeding that contains a high percentage of water, protein, and vitamins but a lower percentage of fat than the hind milk that is released later.
SEE: hind

goat's milk

Milk obtained from goats. Goat's milk should be pasteurized before use. It differs from cow's milk in that it has a higher fat content but is deficient in folacin and vitamin B12.

hind milk

Milk released at the end of a breast-feeding, distinguished by its high fat content.
SEE: fore milk

homogenized milk

Milk processed in such a manner that fats are combined with the body of the milk without the cream separating.

instant dry nonfat milk

Dried skim milk that may be stored at room temperature until needed and then reconstituted by adding water to the granules. It is often fortified with vitamins A and D.

lactic acid evaporated milk

Evaporated milk to which sugar and lactic acid have been added. To prepare this milk, add 17 oz (503 mL) of water to 13 oz (384 mL) of evaporated milk, 2 level tbsp (1 oz or 28 g) of granulated sugar, and 3 tbsp (45 mL) of vinegar.

low-fat milk 1%

Cow's milk with 1% fat, which represents 22% of the calories.

low-fat milk 2%

Cow's milk with 2% fat, which represents 35% of the calories.

mature milk

Milk released once lactation has become fully established.
SEE: fore milk; SEE: hind milk

modified milk

Cow's milk altered so that its composition more closely approximates that of human milk.

mother's milk

SEE: Breast milk.

nonfat milk

SEE: Skim milk.

pasteurized milk

Milk heated to a specified temperature for a precise length of time and then cooled rapidly. This process kills pathogenic bacteria without appreciably altering the taste of the milk.
SEE: pasteurization

pasteurized donor breast milk

ABBR: PDBM Milk produced by one woman and then pasteurized for use by another woman and her newborn infant when the infant's mother does not make adequate milk to nourish her child.
SYN: SEE: donor milk; SEE: pasteurized donor human milk

pasteurized donor human milk

SEE: Pasteurized donor breast milk.

protein milk

Milk modified to be high in protein and low in carbohydrate and fat.

raw milk

Milk that has been neither processed nor pasteurized.

red milk

Milk contaminated by blood, chromogenic bacteria, or plant pigments.

ropy milk

Milk that has become viscid as a result of exopolysaccharides produced by bacterial contamination.

skim milk

Cow's milk from which the fat has been removed.
SYN: SEE: nonfat milk

sour milk

Milk with lactic acid caused either by lactic acid-producing bacteria or by the addition of vinegar. It is most commonly used in baked goods.

soy milk

A beverage derived from soybeans. It can take the place of cow's milk for people who are lactose intolerant or are allergic to milk proteins.

sterilized milk

Milk that has been boiled to kill bacteria.

transitional milk

The first breast milk produced as colostrum production decreases. It has more triglyceride and medium-chain fatty acid content than colostrum. Its other components include lactose, water-soluble vitamins, and immunoglobulins.

vegetable milk

1. The latex of plants.
2. A beverage prepared from juices of various plants, such as soybean.

vitamin D milk

Milk in which vitamin D content has been increased by addition of concentrates, ultraviolet irradiation, or feeding of irradiated yeast to milk-producing animals.

whole milk

Milk whose fat content is unaltered. It is homogenized, pasteurized, and often fortified with vitamins A and D. It may in some instances be treated with lactase-destroying enzymes.
SEE: pasteurization.

witch's milk

1. Milk secreted by the newly born infant's breast, stimulated by the lactating hormone circulating in the mother’s bloodstream.
2. A rarely used synonym for galactorrhea.