Although, as has been explained, the selection and preparation of foods require much consideration from the housewife who desires to get good results in COOKING, there is still one thing to which she must give attention if she would keep down the cost of living, and that is the care of food. Unless food is properly taken care of before it is cooked, as well as after it is cooked--that is, the left-overs--considerable loss is liable to result through its spoiling or decaying. Both uncooked and cooked food may be kept wholesome in several ways, but before these are discussed it may be well to look into the causes of spoiling. With these causes understood, the methods of caring for foods will be better appreciated, and the results in buying, storing, and handling foods will be more satisfactory.

To come to a knowledge of why foods spoil, it will be well to note that nature abounds in micro-organisms, or living things so minute as to be invisible to the naked eye. These micro-organisms are known to science as microbes and germs, and they are comprised of bacteria, yeasts, and molds, a knowledge of which is of the utmost importance to the physician and the farmer, as well as the housewife. Just in what ways these are beneficial to the farmer and the physician is beyond the scope of the subject of COOKING, but in the household their influence is felt in three ways: They are the cause of the decay and spoiling of foods; they are of value in the preparation of certain foods; and they are the cause of contagious diseases. It will thus be seen that while some microbes are undesirable, others exert a beneficial action.

It is only within comparatively recent years that the action of micro-organisms has been understood. It is now definitely known that these minute living things seize every possible chance to attack articles of food and produce the changes known as fermentation, putrefaction, souring, and decay. Micro-organisms that cause fermentation are necessary in bread making and vinegar making, but they are destructive to other foods, as, for example, those which are canned or preserved. Organisms that cause putrefaction are needed in the making of sauer kraut, salt rising bread, and cheese. Molds also help to make cheese, but neither these nor putrefactive organisms are desirable for foods other than those mentioned. It should be remembered, however, that even those foods which require micro-organisms in their making are constantly in danger of the attacks of these small living things, for unless something is done to retard their growth they will cause food to sour or decay and thus become unfit for consumption.

Some foods, of course, withstand the attacks of micro-organisms for longer periods of time than others. For example, most fruits that are protected by an unbroken skin will, under the right conditions, keep for long periods of time, but berries, on account of having less protective covering, spoil much more quickly. Likewise, vegetables without skins decay faster than those with skins, because they have no protective covering and contain more water, in which, as is definitely known, most micro-organisms thrive.

If food is to be kept from decaying, the housewife must endeavor to prevent the growth of micro-organisms, and she can best accomplish this if she is familiar with the ways in which they work. It is for this reason that, whether she possesses a scientific knowledge of bacteria or not, an understanding of some practical facts concerning why food spoils and how to keep it from decaying is imperative. In this part of COOKING, as in every other phase, it is the reason why things should be done that makes all that relates to the cooking of food so interesting. In all parts of the work there are scientific facts underlying the processes, and the more the housewife learns about these, the more she can exercise the art of COOKING, which, like all other arts, depends on scientific principles.