consistency, various coloring and flavoring materials, as well as
bacteria, are added to the curd. The action of these bacteria is really
the chief factor in the making of cheese and they are therefore not only
desirable but necessary. Non-desirable bacteria, however, result in the
formation of bad odors, flavors, and gases in the finished product and
these must be carefully guarded against by cheese makers.

[Illustration: Fig. 3]

20. Cheese offers a valuable source of nutriment for the body, because
its food value ranks high. As is shown in Fig. 3, the food value in 1
pound of cheese is equivalent to that in 2 pounds of beef, that in 24
eggs, or that in 4 pounds of fish. The use of cheese, however, is not
nearly so great as its food value warrants, the amount used in the
United States per capita being only about 3-1/2 pounds annually. This is
a condition that should be overcome, for there is a large variety of
ways in which cheese can be used to advantage in the diet. When eaten
raw, it is very appetizing, and when used with soups, sauces, and foods
that have a bland taste, it lends additional flavor and makes an
especially attractive dish. In addition, the fact that it is an
economical food and can be conveniently kept and stored should recommend
its frequent use.

21. COMPOSITION OF CHEESE.--Since cheese is a product of milk, it is
somewhat similar to milk in composition, but the change that occurs in
the formation of cheese causes some differences. Nearly all the water
present in milk is removed during the manufacture of cheese, so that
this product becomes a concentrated food made up of all the nourishment
that milk contains except small amounts of albumin, milk sugar, and
mineral matter. These, because they are in solution in the water, are