Chapter X).

Whole milk and the milk products, cream, butter, and cheese, are all important food materials among the nations of the western world; and the manufacture of milk products, such as condensed milk, butter, and cheese, has developed large industries. While the Chinese and Japanese are two great peoples who have not utilized milk or any of its products as food for grown people to any extent, yet we are fully justified in counting these foods among the necessities. Nothing can fully take the place of milk in the family dietary.

Figure 41 shows how all the foodstuffs are represented in milk. When milk first comes from the cow the fat is suspended in tiny, invisible particles throughout the water, giving the milk its yellow tint, and the fat rises to the top in the form of cream after a few hours. The protein, sugar, and ash are dissolved in the water. When milk reaches the stomach, the protein separates from the water in the form of curd. This change is brought about by an enzyme (soluble ferment) called rennin, which is present, along with pepsin, in the gastric juice. Curd is also formed by the souring of milk through the action of bacteria, or by adding acid directly to the milk. Milk should never be gulped down, but taken in sips, so that only small portions of curd are formed in the stomach, because these are much easier to digest than large ones. Sometimes milk is soured purposely, as in buttermilk or zoolak or matzoon, that curds may form and be beaten fine before it is drunk. This is very easy to digest, because then no large curds can form. For the same reason, it is often better to take milk with bread or some other food, or to cook it in some dish. Skim milk is a valuable food, for it has everything found in whole milk but the fat. We miss the flavor of the fat in drinking it, hence it is better to use it in pudding or soup or in cooking cereals where we do not care so much about the milk flavor. Study Fig. 41, comparing the percentages of the foodstuffs in whole, skim, and buttermilk, and cream. Notice that the skim milk is higher than the whole milk in protein and sugar, that it has as much ash, and a trace of fat even. It does not tell us, however, that the forms of ash in milk are most valuable, and that it is richer in calcium than any other food material. How these foods compare in fuel value is shown in Fig. 42.

=Wholesome and clean milk.=——At present, the milk supply is one of our most pressing community problems, showing how closely the country and the city are united. A case of typhoid fever in one farm family, not properly cared for, may be the seed of a serious epidemic in some town. To insure clean milk to the consumer, and a fair return in money to the producer, is a great sanitary and commercial problem, not to be solved in a day.

Milk is a medium in which bacteria flourish, both the harmless and the disease producing. Typhoid fever and other fatal diseases may be carried by milk from unclean barns and dairies, and tuberculosis is possible from diseased cows. The cows must be in good health, and the stable clean. Figure 43 shows a stable with cement floor and good drainage. The cows must themselves be clean, and should be curried and washed. The milkers should have clean clothes and hands, and all receptacles should be sterilized. The milk must be rapidly cooled (see Fig. 44), bottled in sterilized bottles, kept cool during transportation, and delivered as promptly as possible to the consumer. “Certified” milk is produced and handled under the best conditions, but costs at least 15 cents a quart. Since a quart of milk is equivalent to a pound of steak or to 8 eggs, milk even at 15 to 20 cents a quart is more economical than meat and eggs at ordinary prices. At the usual price of 8 to 10 cents a quart, milk is very economical as compared with other perishable foods.

The question of preservation and pasteurization can be treated here but briefly. Preservatives are forbidden by law in most states. Pasteurization is heating at a temperature sufficiently high to kill any disease germs present, but not high enough to give a cooked taste. This process, while it destroys most of the bacteria, does not kill the spores of all. The chief arguments against pasteurization are (1) that on a commercial scale it is difficult to really accomplish this, and (2) that it is easily used to cover the sale of unclean milk. The argument for it is, that it is impossible to obtain as yet an ideal supply for a large city in hot weather, and that pasteurization, if properly conducted, kills nearly all of the dangerous bacteria and saves the lives of many babies. Clean milk that needs no pasteurization is our ultimate aim, and we must remember that milk pasteurized under unknown conditions needs to be kept cold and treated with even more care than fresh milk, for it “spoils” quite as easily, only we may not know it because it may not taste sour.

In the last few years the question of pasteurization has been studied with very great care. It is found best to heat the milk for 20 to 30 minutes at a temperature of 140° to 155° F. If it is certain that this method has been used, one need not hesitate to trust the milk, for the arguments against pasteurization do not properly apply here.

=How to buy.=——Investigate by question and inspection, if possible, the available milk supply. Be sure to do this in the country in the summer. Always buy bottled milk. Where the income is small, good quality milk should be used for the little children and invalids, and skim milk purchased for cooking. In many places skim milk is supplied in bottles by reliable firms. The usual price for bottled milk in the city is 8 to 10 cents, and this is of good average quality. Keep milk cold. If there is no ice, use an ice substitute (page 74), and in very hot weather pasteurize or scald the milk, cooling afterward as quickly as possible by placing in cold water and stirring the water.

GENERAL METHODS AND RECIPES

=Principles of cookery.=——Clean, sweet milk is an ideal food, which requires no cooking. Heating milk to 212° F. changes its properties in some way, so that it is not considered an ideal food for babies’ regular diet. If it must be used, for reasons of safety, some uncooked food, such as orange juice, should also be given. This is the reason for pasteurizing milk instead of boiling it.

Heating milk in an open vessel causes some of the protein to harden into a thin “skin” on the top. This can be prevented by stirring the milk until it is cool.

=1. To pasteurize milk.=

This cannot be done accurately without a thermometer. The milk bottle should be placed upon a rack in a kettle of water, with a clean thermometer inserted through the cover of the bottle. Heat the water slowly, and watch the thermometer. When it reaches 155° F., see that the water becomes no hotter. Set the kettle on a rack on the stove top, or use a simmering burner with rack and asbestos mat. It is difficult to keep the temperature even, but it should remain at 140-155° F. half an hour. At the end of half an hour, the bottle should be removed, and cooled as rapidly as possible in running cold water.

=2. Rennet custard.=

1 quart milk, two tablespoonfuls of sugar, a shake of salt, flavoring, 1 rennet tablet. The flavoring may be: 1 teaspoonful vanilla, _or_ a few tablespoonfuls of orange juice, _or_ the vanilla, plus three or four tablespoonfuls of cocoa to suit the taste.

_To prepare._——This is a process without cooking. Rennet tablets are made from the stomach of the calf, and contain the digestive enzyme, rennin, which results in the solidifying of the curd of the milk. Rennet custard has passed the first stage of milk digestion.

Put all the flavoring substances into the milk, and warm it slightly, not more than 100° F. The cocoa when used should be “dissolved” in a small amount of hot water. Dissolve the rennet in a tablespoonful of cold water, and stir this very thoroughly into the milk. Pour the milk into the cups in which the custard will be served, and set the cups in a warm but not hot place. A good method is to place them in a pan of warm water (100° F.). The milk becomes firm in a half hour or an hour, and as soon as it is set, should be put in the ice box, otherwise the process continues and the custard becomes watery as the curd shrinks and forces out the whey. Serve very cold with fruit on the top, or whipped cream with the cocoa flavoring; or put grated nutmeg or powdered cinnamon on the top. This is a simple and delicious dessert, and one of the most wholesome. For children it should be flavored with fruit juice or vanilla rather than with cocoa.

=3. Uses of sour milk.=

Do not throw away any sour milk that is clean and not stale. Milk that has soured enough to set, is a delicious dessert, with cream and sugar. The acid is very pleasant, being the same as that of buttermilk. Sour milk is better for griddlecakes and muffins than sweet milk. (See Chapter XI.) Another excellent use for sour milk is to make it into cottage cheese. (See below.)

=Matzoon= and other similar preparations are essentially soured milks, prepared under controlled conditions. These preparations are the common form of milk in certain parts of the Orient, where milk is never used sweet.

=Kumyss= is milk slightly soured and fermented with one species of yeast. This is a Russian method. These preparations are excellent for invalids and exhausted people, for they can sometimes be assimilated because of the fine curds when sweet milk cannot.

=Condensed milk= is a practical method of preserving milk. The milk is evaporated under pressure at a high temperature in apparatus constructed for the purpose. Cane sugar or glucose is sometimes added. A new patent process condenses the milk at low temperature, preserving it for a short period, as compared with the condensed milk in tins, but it keeps well for several days, and bears transportation. Condensed milk may be used in cooking, when clean fresh milk is not available. The unsweetened kinds are most useful, but, like pasteurized milk, must be treated with care after the cans are opened.

=Cheese.=——Cheese is made from the curd of milk, and contains the most nutritive parts of the milk in highly concentrated form. In the process of manufacture, the milk is first curdled by rennet, and the whey strained out. The curds after preliminary treatment, varying according to the style of cheese to be made, are finally pressed together very slowly in a cheese press, which is screwed down more tightly as the cheese becomes dryer. The cheeses are then covered with cheesecloth and “ripened” slowly, the ripening process giving characteristic consistency and flavor. This ripening is due to the action of bacteria and molds. (See page 97.) Foreign varieties of cheese, made originally in some one locality, have marked colors, quality, and flavors, as Brie, Camembert, Roquefort, and the Swiss cheeses. Parmesan is an Italian cheese, excellent with macaroni and spaghetti.

_American cheeses_ vary in color, in strength of flavor, in creaminess, and in degree of hardness. Much the greater part is, however, of the general type known as “American cheddar” or “standard factory” cheese.

_Club cheese_ is an American cheese of good quality, put up in small jars. It is a soft cheese, excellent to serve with crackers, but is too expensive for common use.

_Cottage cheese_ is a home product made from sour milk, and used at once.

=Composition and nutritive value.=——Cheese is high in protein, and usually in fat. (See Fig. 40.) Note the small amount of water, which makes cheese a very concentrated food. The protein content makes it a meat substitute, for those with whom cheese does not disagree. Being a dense as well as concentrated form of food, it should be eaten in small quantities, and in combination with other food materials in such a way that it will become finely divided, or it will not be easily digested. The ash content is high, the most valuable of the ash constituents of the milk being retained in the cheese.

=The cost of cheese.=——The foreign cheeses are expensive, but American cheeses may be classed among the moderate priced foods and they compare favorably with other protein foods.

Cheese costs more than beans, and less than most cuts of meat. A good American cheese costs about twenty-five cents per pound. Taking account of composition as well as cost per pound, we find that a given amount of money buys about twice as much food value when spent for cheese as it would if spent for beef. See Fig. 45.

=Care of cheese in the pantry.=——Cheese should be kept dry and covered, that its odor may not be noticeable. Soft cheese should be kept in the ice box. The receptacle for cheese should be thoroughly sterilized before each new purchase is put away.

GENERAL METHODS AND RECIPES

=1. Uncooked cheese.=——Serve a cream cheese with a salad of lettuce, and the imported cheeses with crackers and fruit for dessert. American cheese may be thinly sliced and used in sandwiches. A small piece of cheese with apple pie or pudding is an old-fashioned combination that is always agreeable, but sometimes difficult of digestion.

=2. Cottage cheese.=

Use sour milk that has set. Other ingredients: salt to taste, cayenne pepper or paprika, if liked. Quality and flavor are improved by the addition of a tablespoonful of butter or two tablespoonfuls of cream to a pint of the curd, but these are not necessary.

Warm the milk slowly, until the whey begins to separate from the curd. If this process is continued too long, and the milk becomes hot, the curd will be tough. Place a piece of cheesecloth over a bowl, pour in the curds and whey, and lift the cloth carefully, allowing the whey to run through. Squeeze out the remaining whey. Add the seasoning and other ingredients to the curd, shape in balls, and chill before serving. It is delicious served with lettuce and dressing as a salad, or with gingerbread for dessert at luncheon or supper.

=Principles of cooking cheese.=——The fat in the cheese is melted by heat. The protein is toughened by a high temperature, therefore a low temperature process should be used.

=3. Cheese cooked with other food materials.=——A creamy cheese should be selected for cooking. Cheese may be grated and sprinkled on the top of potato on the half shell, or any other mashed potato; or it may be sliced and placed with each layer in escalloped potato. Its use is common with macaroni; and a dish of macaroni with milk and cheese is a good meat substitute, and may be used as the main dish of a luncheon or simple dinner. Those to whom cheese is agreeable will find many places for its use. Its flavor harmonizes with celery and with tomato. The Italians serve grated Parmesan cheese with soup, and with spaghetti that has a tomato sauce.

=4. Cheese crackers.=——Select crackers of a firm quality that will not crumble or flake easily, and of a small size. Spread very thinly with soft butter, put the crackers in a pan, and sprinkle grated cheese upon each one. Set the pan in a moderate oven until the cheese is melted. A sprinkling of paprika may be used. Serve with lettuce, celery, or other green salad.

EXERCISES

1. Compare the composition of eggs, milk, and cheese.

2. How may an egg which has been kept too long in cold storage be detected?

3. What is the effect of the boiling temperature of water upon an egg?

4. Compare a hard- and a soft-cooked egg for digestibility.

5. What are the dangers from unclean milk?

6. How may the milk supply be safeguarded?

7. Why is cheese a meat substitute?

8. What caution should we exercise in using it?

9. What precaution must we take in cooking cheese?