(b) Ingredients.—(1) Milk.—The selection of milk for an infant is an important consideration. Clean milk is most essential. Milk is considered clean when it comes from dairy farms where clean milkers work under sanitary conditions, approved by a medical milk commission (see Care of Milk). Such milk contains few bacteria and is called certified milk. This is by far the safest milk for infant diet, but it is expensive. It usually costs almost twice as much as ordinary milk. Milk is pasteurized commercially by heating it to 150 degrees F., keeping it at that temperature for about thirty minutes, and then quickly cooling it. While pasteurizing kills most of the disease-producing germs, it does not destroy all the spores (see Microorganisms in theSpore Form). The taste of milk is not affected by pasteurizing. Milk is sterilized—all germ life destroyed—by heating at 212 degrees F. from one to one and one half hours.
Since the value of milk as an infant food depends upon its cleanliness, it is difficult to state just how old milk may be before it is unsafe for infant feeding. It is safest to use only fresh milk. Bacteria in milk may develop so rapidly that it is unfit to use a few hours after it has been drawn from the cow. Unless milk is certified, it should not be used in summer after it is twenty-four hours old, and in winter, after it is forty-eight hours old. Bottled milk should be used for infants. According to most plans for modifying milk, whole milk is used.
(2) Sugar.—Several kinds of sugar are used in modified milk. These are:
Milk sugar or lactose.
Malt sugar combined with dextrin or dextrimaltose.
Granulated sugar or cane sugar.
The advice of a physician should be consulted regarding the kind of sugar best suited to the needs of the particular infant. The first two kinds of sugar can be obtained at a drug store. Granulated sugar is too sweet for general use.
(3) Water or Cereal Water.—If plain water is to be used with milk, it should be boiled before adding to the other ingredients.
In some cases, gruel or cereal water is added. Usually rolled oats or barley flour is the grain used. To prepare either of these use:
4 tablespoonfuls rolled oats or 3 tablespoonfuls barley flour 1 quart cold water
Mix and boil gently until the mixture is reduced to a pint. Then strain through a fine wire strainer or muslin.
[Illustration: Figure 87.—Graduated Measure and Dipper for Measuring the
Ingredients of Modified Milk.]