Cheese may well be used as a chief source of nitrogenous food, since it contains the valuable protein part of milk together with its mineral salts. It contains three fourths of the total solids in milk, which gives it nearly twice as much protein as an equal weight of beef of the average composition as purchased. With its 33 per cent of fat, the fuel value is more than twice as great. The composition of cheese is easily remembered because it is divided in a general way between protein, fat, and water, about 33 per cent of each. There are other reasons for its importance in the diet; it can be kept and handled with great ease in the home, it has an appetizing flavor, and it can be served in a great variety of ways.

Food value

Three fourths of the amount of cheese produced in the United States is standard factory or American cheese, usually made from whole cow's milk. The protein or casein of the milk is thrown out by the action of rennet forming a curd. It carries most of the fat of the milk with it. This curd is broken by knives and then heated to differing degrees. The whey is drained off; the curd salted and pressed. The curd is then kept for several weeks in a cool place to ripen, or to develop the flavors by means of the action of bacteria or molds. This ripening process is the chief cause of the flavors of different cheeses, although of course the variety of flavor also depends somewhat on the type of milk used. The soft cream cheeses contain more water than an ordinary factory cheese, since they are not drained under pressure, nor are they allowed to ripen so long. They are usually made from rich cream by souring or by the action of rennet, and after the whey is drained off the curd is salted, turned occasionally, and is ready for market in five or six days. Some cheeses, such as Roquefort and Gorgonzola, are ripened by molds growing throughout the cheese. The tale is told of the origin of the Roquefort cheese that a goatherd one day was interrupted while eating his lunch of bread and cheese, and being a thrifty lad, put what was left on a ledge in a near-by cave. He forgot about it, but when in that neighborhood again some time later, he looked to see if it was still there. To his surprise he found that in place of the ordinary farm cheese which he had left, he had a most delicious cheese streaked with green mold. He took it back to the village and showed it with pride to his mother and the other village women. For years after, the villagers put their cheese to ripen on the ledges in that cave and in the neighboring ones. They found, however, that they must also place bread with the cheese in order to get the characteristic mold. Nowadays, however, since the scientists have isolated the various molds and bacteria for us, Roquefort cheese, as well as Swiss and Dutch and other varieties, can all be turned out from the same American factory.

Kinds

Ripening

The Dutch women are very careful that no molds shall be allowed to grow on their cheese, since they depend entirely upon the bacteria present in the milk to produce the proper flavor in the ripening process. They carefully dust their cheeses every day while ripening and when they are ready for market, they paint them red or give them a coat of varnish to prevent any molds from spoiling the flavor.

A cheese like Camembert is ripened by bacterial action on the outside which gradually works in, softening the cheese.

Other hard cheeses, such as Swiss, Parmesan, and English dairy cheeses, are ripened by bacteria and enzymes, or unorganized ferments, working on the inside. All these changes increase the solubility of the proteins and produce the peculiar flavor of each cheese.

When we speak of cheese as a meat substitute, we refer only to that mild-flavored cheese known as the American factory cheese which can be used in large quantities. The other cheeses, which are used in small quantity primarily for their flavor, belong to the class of luxuries that fall "in the region of choice." They are the ones that are referred to in the cynical remark that "cheese digests everything but itself," since their strong flavor is an aid to digestion.

Ordinary cheese compares favorably with other foods in the thoroughness with which it is digested in the body; for over ninety per cent of its nutrients are available. It is slow of digestion, however, because of the intimate combination of fat and protein material. The burning sensation sometimes felt after eating cheese is due to the presence of free fatty acids in the cheese, that are caused by overcooking which decomposes the fat. Another reason why cheese may cause uncomfortable sensations is due to the way in which it is used. A Welsh rarebit eaten late in the evening after three good meals have already been consumed may cause a restless night, but the cheese should not be blamed for the nightmare, since the body has already had all the food required for the twenty-four hours and objects to the added burden placed upon it at that hour.

American cheeses are usually shipped in cakes of twenty-six or thirty-two pounds apiece, and are wrapped in heavy canvas. When cut and delivered at the house, care should be taken that cheese does not dry and that it does not be-come moldy. It should be wrapped in a slightly damp cloth and kept in a cool place. Air should never be wholly excluded from it, since molds grow more readily in the absence of air.

When planning a meal in which cheese is to take the place of meat, great care should be taken with the foods used in combination with it. It is not well to substitute cheese for the meat and leave the rest of the meal the same. The reason for this is that cheese is a more concentrated food than meat, containing a larger proportion of fat and protein and much less water. It must be used along with watery foods like fruits and vegetables. As it is also entirely lacking in any form of carbohydrate, it is well combined with starchy dishes, bread, rice, or macaroni. All cheese dishes are apt to be soft in consistency, so that in order to get variety and increase the palatability of the meal, it is well to include in the menu hard foods, such as toast, crisp buns, or hard cookies. A cheese souffle might be accompanied by a baked potato, crisp cinnamon buns, two green vegetables, with a fruit salad or stewed or baked fruit and crisp cookies for dessert.

Digestion

Care in the home

Use in the diet