lost when the whey is separated from the curd. The food substances that
occur in the largest amounts are fat and protein in the form of casein,
which is the tissue-building material of milk. Cheese made from milk
that contains some cream has in it a greater amount of fat than that
made from completely skimmed milk. Besides these two chief food
substances, cheese contains a small amount of milk sugar, mineral
matter, and water.

22. On account of the large quantity of protein found in cheese, this
food can readily take the place of meat in the diet; in fact, it has
some decided advantages over meat. As has been pointed out, cheese
yields more than twice as much food value as an equal weight of beef.
Then, too, the buying and care of cheese are much simpler matters than
the buying and care of meat. As it does not require the low temperature
that meat requires and does not spoil so readily, it can be bought in
considerable quantity and used as desired without danger of spoiling and
loss. In addition, the use of cheese as food does not require so much
skill in preparation as meat does, nor is there loss of flavor and
nutriment in its preparation, as is often the case with meat.

23. QUALITY OF CHEESE.--Every variety of cheese has its own standard and
quality, some being hard and dry, others moist, and still others very
soft. The difference in quality is due to the way in which the curd is
coagulated, the amount of pressure that is put on it, and the ripening
of the cheese. The holes that often occur in cheese and give it a porous
appearance are formed by gas, which is the product of the growth of
bacteria. A large number of very small holes in cheese indicate that
the milk used to make it was not clean and contained many kinds of
bacteria. This condition could be overcome by the use of absolutely
clean milk; indeed, milk of this kind is as necessary for the production