PART IV.

MILK AND MILK PRODUCTS AND OLEOMARGARINE.

MILK.

=Limitation of Name.=--By the term “milk,” unless qualified in some way, is meant a lacteal secretion of the healthy cow, free of colostrum and of standard quality. If the milk of other mammals is meant the name of the class of animal is used in connection with the term, such as ewe’s milk, goat’s milk, etc. Milk is one of the most important articles of commerce and, by reason of its composition, high nutritive character, and easy digestibility, it is not only the natural food of infants but a most important food for children and adults. It is also an indispensable food in many, if not most, cases of disease where nutrition is impaired. In some cases life may often be sustained over a critical period by the use of milk as a food where other forms of food would fail of digestion and prove injurious instead of beneficial.

The United States standard for milk is found in Appendix A.

=Average Composition of Milk.=--Perhaps there is no food substance which has been subjected to so many and such severe analytical tests as milk. Hundreds of thousands of analyses have been made in all civilized countries, not only of the milk of the individual cow but of herds of greater or less size.

There is a great variation in the composition of milk in different breeds of cattle and also in different individuals of the same breed. For instance, the Holstein breed of cattle affords a milk with a very low content of fat, sometimes as low as 3.25 percent, and in individual cases lower. On the other hand the Jersey breed of cattle affords a milk of a very high content of fat, sometimes reaching as high as 6 percent, and in individual cases very much higher. The content of the nitrogenous element in milk is more stable than that of fat and the common content of casein in milk ranges from 2¹⁄₂ to 3¹⁄₄ percent. The sugar in the milk is usually the complementary substance with the fat, diminishing in relative proportions as the fat increases and vice versa. The average content of sugar in cow’s milk is approximately 4 percent. The content of mineral substances in milk is also quite constant, being about 0.70. The ash contains the phosphoric acid which is one of the essential food components of milk. A milk of fair average quality contains 12 percent of solids and 88 percent of water. This is an expression for milk during the various seasons of the year and from all breeds and kinds of cows. The influence of season has much to do with the quantity of milk produced. It is always greater in the spring and summer months, when the cows are turned out to pasture and the growth on which they feed is unusually succulent. The increase in volume is not attended with a proportionate increase of solids, and thus the percentage of solids in spring and summer milk is less than that in the winter milk unless the cows are particularly well fed during the winter on a generous diet, including large quantities of roots.

The character of the milk is greatly influenced by the environment in which the cow lives. The stable in which the cow is kept should be clean, well ventilated, and protected against extreme changes in temperature, thus being cooler in the summer than the hot air on the outside and much warmer in the winter. An excellent arrangement of the stables to secure cleanliness and good ventilation is shown in Fig. 13. Cows should be supplied with an abundant quantity of pure water and should not be allowed access to stagnant pools when pasturing in the summer. Every animal giving milk should be examined from time to time by a competent veterinarian to determine, by the injection of serum or otherwise, whether or not the animal is afflicted with tuberculosis. Every animal infected with tuberculosis should be separated from the herd and destroyed. Tuberculosis is an infectious disease and may spread from a single cow to every one in the herd. It is still by some authorities claimed that there is no authentic case of transmission of bovine tuberculosis to the human system. Other authorities hold that such transmission is possible, even if it has not been proven in a particular case. Since experts disagree on this point the same rule is applicable here as in other cases of the same kind, namely, where experts disagree on a point relating to the public health the benefit of the doubt, if any, should be given to the public, and the advice of those experts followed which is the most radical respecting the protection of health from infection of any kind. It would be difficult to prove, for example, in any case of tuberculosis in man that it had been contracted from the sputa of tuberculosed patients, yet because it is possible, in the opinion of many experts, that such infection and transmission of disease can take place, it is the part of wisdom to guard against it.

It is, I think, a statement which will be accepted by all that it is possible in this country to secure and keep a sufficient number of healthy cows to give the milk supply of the nation. Therefore, it is the duty of the state, either by municipal, state, or federal inspection, to eliminate, as far as possible, and, if necessary, at the expense of the state, every diseased animal from the dairy herd. The farmer whose herd becomes infected through no fault of his can justly claim a compensation for the destruction of his animals for the common good. There is, perhaps, no more important point connected with the keeping of sanitary conditions than the proper inspection of the dairy, not only furnishing milk for family use, but especially for sale. It is the plain duty of every municipality and state to prohibit the sale of milk to its citizens from dairies which are not periodically and frequently subjected to the most rigid expert inspection. Such inspection would not only secure the health of the animals but tend directly toward the cleanliness of the dairy. Only by the exercise of unusual care is it possible to keep milk from becoming contaminated.

=Preparation of Milk.=--Every part of the animal, especially the udders, should be kept scrupulously clean by proper currying and washing. The milk should be collected in vessels with as small an orifice as possible. As soon as drawn the milk should be strained and artificially cooled to a temperature of at least 50 degrees F., if not lower. A convenient apparatus for cooling the milk is shown in Fig. 14. In this condition, without being exposed to infection and being protected from every point by closed vessels, stoppered when necessary by sterilized cotton, the milk is conducted into sterilized bottles and again stoppered with a sterilized cork of some description. The milk is kept cold until delivered to the consumer and by the consumer should be kept cold until used. By following these precautions it is possible to deliver a pure, wholesome, unpasteurized milk in a condition which keeps practically unchanged for even a longer period than twenty-four hours.

=Certified Milk.=--Dairies which are inspected either by operation of the law or, voluntarily, by a competent body of medical and scientific experts duly authorized to make such inspection furnish to the market what is known as certified milk. Each bottle of this milk bears the stamp of certification and this stamp may be used from the time of one inspection until a certain date specified on the stamp when the next inspection takes place. The duty of the inspectors is to see that diseased animals are at once removed from the dairy, that the sanitary conditions of the stable are perfect, that the food is abundant and wholesome, that the milking process is conducted according to the principles above outlined, and that the proper precautions are taken to prevent infection during the preparation of the milk for the market. The milk should be examined chemically and bacteriologically at each inspection, or oftener, to see that it is of a standard quality, both in respect of the number and character of the organisms which it contains and of its chemical constituents. Certified milk is, of course, more expensive than non-certified, inasmuch as the dairy is necessarily called upon to bear the expense of inspection. However, the superior quality of such milk and its certain freedom from infection more than offsets the increased price, and makes certified milk the ideal food of a milk character, not only in the family, but especially in the hospitals, orphan asylums and other public institutions. It seems quite certain that in the near future practically all the milk that is sold upon the market of the country will be of a certified quality.

=Pasteurized Milk.=--When milk is heated to a temperature of about 140 to 160 degrees the greater part of the living organisms contained therein are destroyed. At the same time the temperature is not high enough to give to the milk that peculiar taste which it acquires when boiled. Such pasteurized milk, placed in sterilized bottles, stoppered with sterilized stoppers and kept in a cool place, will keep many days and even weeks without apparent deterioration. Physicians and hygienists are quite agreed that pasteurized milk is not so wholesome, especially for children, as certified milk which has not been subjected to a heat sufficiently high to kill the organisms contained therein. The natural ferments of the milk, namely, the enzymes which produce the lactic fermentations, promote rather than interfere with the digestion of the product. The killing of the beneficial organisms of the milk is only justified when there is danger of pathological germs being present. Hence the pasteurization of milk must in this sense be regarded as a substitute for inspection and certification.

There may arise cases where pasteurizing even of certified milk may be desirable, namely, when from necessity it must be kept for a considerable period before use, as on shipboard, and other places inaccessible to a daily supply of fresh milk. Pasteurizing is also justifiable in miscellaneous milk supplies, the origin of which is unknown. It is safer, by far in this case, to pasteurize than take the chance of consuming pathological germs.

=Pasteurizing of Milk.=--A convenient method of pasteurizing milk is recommended by the Dairy Division of the Department of Agriculture, which is as follows:

=Directions for the Pasteurization of Milk=.[20]--The pasteurization of milk for children, now quite extensively practiced in order to destroy the injurious germs which it may contain, can be satisfactorily accomplished with very simple apparatus. The vessel containing the milk, which may be the bottle from which it is to be used or any other suitable vessel, is placed inside of a larger vessel of metal, which contains water. If a bottle, it is plugged with absorbent cotton, if this is at hand, or in its absence other clean cotton will answer. A small fruit jar loosely covered may be used instead of a bottle. The requirements are simply that the interior vessel shall be raised about half an inch above the bottom of the other, and that the water shall reach nearly or quite as high as the milk. The apparatus is then heated on a range or stove until the water reaches a temperature of 155 degrees Fahrenheit, when it is removed from the heat and kept tightly covered for half an hour. The milk is rapidly cooled without removing it from its containers and kept in a cool place. It may be used any time within twenty-four hours. A temperature of 150 degrees maintained for half an hour is sufficient to destroy any germs likely to be present in the milk, in cold weather, or when it is known that the milk reaches the consumer soon after milking, and it is generally safe to adopt this limit. It is found in practice that raising the temperature to 155 degrees and then allowing the milk to stand in the heated water for half an hour insures the proper temperature for the required time. If the temperature is raised above 155 degrees the taste and quality of the milk will be affected.

[20] By Dr. De Schweinitz.

Inasmuch as the milk furnished to consumers in large cities in summer contains at the time of delivery an immense number of miscellaneous bacteria, this procedure may not fully meet the requirements during hot weather, not only because such milk will not remain sweet for twenty-four hours unless kept in a good refrigerator, but also because the bacteria not destroyed by the heating may at times produce digestive disturbances in the very young. Under such circumstances it is best to keep the bottles in the water until it boils or to use one of the many steamers now on the market. After the bottles have been kept at the boiling point for three to five minutes (or longer if they are large) they should be cooled as promptly as possible and kept in a refrigerator until used.

The simplest plan is to take a tin pail and invert a perforated tin pie-plate in the bottom, or have made for it a removable false bottom perforated with holes and having legs half an inch high to allow circulation of the water. The milk-bottle is set on this false bottom, and sufficient water is put into the pail to reach the level of the surface of the milk in the bottle. A hole may be punched in the cover of the pail, a cork inserted, and a chemical thermometer put through the cork, so that the bulb dips into the water. The temperature can thus be watched without removing the cover. If preferred, an ordinary dairy thermometer[21] may be used and the temperature read from time to time by removing the lid. This is very easily arranged, and is just as satisfactory as the patented apparatus sold for the same purpose. Any other simple method of procedure will give the same result.

[21] Before using the dairy thermometer it is best to have it tested, as it may be unreliable in the upper parts of the scale.

_Average Content of Fat in American Milk._--From the thousands of analyses of American milks that have been made it appears that the average content of fat therein is about 3.90 percent. Of the different breeds of cows the Holsteins produce milk with the least content of fat and the Jerseys with the greatest. It is not unusual to find in the milk of a Jersey cow a content of 6 or 7 percent of fat.

=Comparison of Cow’s Milk with Other Varieties.=--Human milk differs from milk chiefly in having a much lower content of casein and a higher content of milk sugar. Goat’s milk has a higher content of casein than milk, somewhat higher content of fat, and slightly less sugar. Ewe’s milk is very rich both in protein and fat. Mare’s has a low casein and fat content and is exceptionally rich in sugar. Ass’s milk has less casein and protein than milk but more sugar.

=Cream.=--When milk is allowed to stand for some hours in a cool place or when it is mechanically treated in a separator the fat particles, being of a less specific gravity, are separated, and when they reach a certain degree of consistence they form a product known as cream. The quantity of fat in cream varies according to the method of separation. On standing for a period of about twelve hours in a cool place the separated cream may be removed by skimming and should contain at least 18 percent of milk fat. Under the action of the separator, cream of a much greater content of fat is usually produced, often reaching as much as 30 percent or more. The separation of cream mechanically in a separator is preferable to the method of time separation by gravity alone. The cream secured by the separator is very much fresher, as it can be removed as soon as the milk is drawn and cooled. Its content of butter fat can also be regulated to the desired amount and, in the third place, a more complete separation is secured than by gravity. By the proper manipulation of the separator almost all of the fat in milk is readily removed. Cream should be kept under the same conditions as has been described for sanitary milk. When placed in sterilized containers, properly stoppered and kept cool, fresh cream will keep sweet as long as milk under similar circumstances.

In large dairy industries the separator is practically the only method now employed for securing cream while for farm use the gravity method of standing in a cool place for twelve or twenty-four hours is the commonly practiced method.

Cream is used on the table with fruit and cereal foods and especially in beverages such as tea and coffee. It is also prescribed by physicians for certain diseases and derangement of the digestive organs where the nitrogen content of milk produces irritation and fails of digestion. Cream is not a complete food in the sense that milk is inasmuch as the other constituents of milk are less in proportion as the percentage of fat is increased, yet cream contains at least a part of all the food elements in milk, as, for example, nitrogenous constituent, principally, casein, milk, sugar, and mineral matters.

It must be remembered in this case that the fat is the variable element and as that is increased the proportion of other ingredients, necessarily, is diminished.

The most important use of cream is in the manufacture of butter.

=Standards of Cream.=--The composition of cream varies with almost every sample. The standards for cream vary in different states and cities. The national standard requires 18 percent of fat.

=Skimmed Milk.=--The residue which is left from the removal of cream is known as skimmed milk. Skimmed milk contains the principle part of the nitrogenous constituents of milk, the greater quantity of its sugar and a very large quantity of its mineral matter. It is still a very valuable food product, lacking only the element of fat. When eaten with nuts or other oily food skimmed milk would complete the ration and make a well balanced food. The chief prejudice against skimmed milk is that it has been so often sold for whole milk. When sold and consumed under its own name it is not a fraudulent body and is deserving of a higher place in the dietary than has been ascribed to it. In the large creameries of the country the skimmed milk is usually fed to animals. It is one of the most highly esteemed foods for pigs and poultry, and is largely used for those purposes.

_Composition of Skimmed Milk._--Naturally the composition of skimmed milk would be that of milk corrected for the abstraction of fat. It contains some little fat when prepared by the gravity method and only a very small portion when separated mechanically. The abstraction of the fat increases the relative proportions of sugar and casein.

=Curd Test for Purity of Milk.=--The Wisconsin curd test is conducted as follows: 1. Sterilize milk containers so as to destroy all bacteria in vessels. This step is very important, and can be done by heating cans in boiling water or steam for not less than one-half hour.

2. Place about one pint of milk in covered jar and heat to about 98 degrees F. (Figs. 15 and 16).

3. Add ten drops of standard rennet extract and mix thoroughly with the milk to quickly coagulate.

4. After coagulation, cut curd fine with case knife to facilitate separation of whey; leave curd in whey one-half hour to an hour; then drain off whey at frequent intervals until curd is well matted.

5. Incubate curd mass at 98 to 102 degrees F. by immersing jar in warm water. Keep jars covered to retain odors.

6. After 6 to 9 hours incubation, open jar and observe odor; examine curds by cutting the same with sharp knife and observe texture as to presence of pin holes or gas holes. Observe odor.

7. Very bad milks will betray presence of gas-producing bacteria by the spongy texture of the curd and will have an off flavor.

8. If more than one sample is tested at the same time, dip knife and thermometer in hot water before each time used.

“Normal milk contains practically no organisms but the straight lactic acid bacteria. These germs produce no gas and no bad odors, but purely lactic acid and the curd formed therefrom is such as is represented in Fig. 17.

“Milk contaminated by the introduction of dust, dirt, fecal matter, or kept in imperfectly cleaned cans becomes fouled with gas-producing bacteria that break down the milk sugar and so produce gases and usually undesirable odors.... Therefore milks showing the presence of gas or bad odors in any considerable degree are milks that have been more or less polluted with extraneous organisms or carelessly handled, and as a consequence such milks show a type of curd revealed in Figs. 17, 18, and 19.

=Whey.=--The residue left from milk in the process of the making of cheese is known as whey. Whey consists of that portion of milk which is not precipitated by the rennet and which separates when the casein of milk is coagulated and sets in the process of cheese making. The whey contains the principal portion of the water in milk, the most of the milk sugar therein, and small quantities of butter and soluble nitrogenous portions (albumin) and solid particles which remain suspended in the solution. It may, therefore, be properly considered as milk from which the greater part of the nitrogenous portions and fat particles has been separated. The value of whey as a food product consists chiefly in the milk sugar which it contains. It is not very largely used for human food but is valued as a food for young domesticated animals, especially pigs and poultry.

=Composition of Whey.=--The whey resulting from the manufacture of cheese contains nearly all the foods of the whole milk with the exception of the casein and fat. It is composed of from 6 to 8 percent of solids consisting chiefly of milk sugar, some albumin, a little fat, and about 0.6 percent of mineral matter.

=Koumiss.=--Koumiss originated in Asia Minor in the production of a fermented drink from mare’s milk, which is richer in milk sugar than the lactic secretions of most other mammals. By the fermentation of the milk sugar mare’s milk is converted into a fermented beverage containing a small percentage of alcohol. In this country koumiss is made almost exclusively from cow’s milk and by special fermentation at a low temperature. It is a beverage valued especially by convalescents and invalids and frequently is capable of nourishing the body in diseases which affect the digestive organs when other foods fail of assimilation. It is also a cooling and delicious beverage for those in health when properly prepared and stored.

_Modified Koumiss or Kephir._--Koumiss made from cow’s milk with the previous addition of milk or cane sugar to increase the alcoholic content cannot be regarded as a natural product but rather one to which the term “modified” may be applied. The greater part of koumiss made in the United States from cow’s milk is of this modified variety. Cow’s milk contains on an average about 4 or 5 percent of sugar and does not yield a fermented beverage of a sufficient alcoholic content without reducing the actual sugar content of the beverage below the point of palatability. Cane sugar is usually employed as the modifying agent. While modified koumiss cannot be regarded as of equal value with the natural article made from mare’s milk it is a palatable and wholesome beverage when produced and stored under proper conditions. The quantity of alcohol produced in any case is not very great and the change in composition which renders koumiss so easily assimilable in many cases cannot be due alone to the alcohol formed but to the fermentative changes produced by enzymic action which takes place in the other constituents of koumiss, especially casein during the process of fermentation.

Koumiss or kephir, which is the name applied to koumiss made from cow’s milk, is also prepared with the addition of honey, in the place of sugar, and small quantities of wheat flour, not exceeding 20 parts to 1500 parts of other constituents. Koumiss is sometimes artificially fortified by the addition of small quantities of alcohol, but this practice must be regarded as extremely reprehensible. The alcohol of koumiss is incident to its fermentation and should not be increased beyond the normal amount. One of the important points in the making of koumiss is the control of the temperature which, during fermentation, ought not to rise above 50 degrees in order to get the best results. Koumiss may be made in the bottle in which it is kept, in fact, it is best made so, and its fermentation then resembles that of champagne. During the process of fermentation the bottle should be shaken at least once a day in order that the part which coagulates cannot be unevenly distributed throughout the mass. The bottle should be strong enough to resist the pressure produced by the carbon dioxid which is formed and the cork should be securely tied in. As in the case of champagne it is best to place the bottle with the cork down. Before using, the bottle containing the koumiss should be well shaken in order to thoroughly mix the contents which form a creamy, foamy mass extremely palatable, highly nutritious, and valuable not only as a beverage but in many cases of disease and disordered digestion as a food. In fact the value of koumiss for medicinal purposes, that is for medicinal food, is not thoroughly appreciated by the medical profession. This may be due to the fact that the art of making koumiss is not generally known, and while the general principles upon which its manufacture is based have been set forth it requires an expert to make a palatable and useful article (“British Dairy Farming” by Jas. Long). It is worthy of suggestion now that the use of horses for draft purposes has practically been superseded by the automobile and the trolley that the production of real koumiss from mare’s milk might become a very useful field of industry in the United States. It is perfectly certain that the genuine article must possess properties which are not wholly found in the imitations of koumiss which are so common in this country. It is well understood by physicians that a natural product produced from natural material is always superior in character both as a food and medicine to the synthetic or artificial product. Whenever, therefore, a fermented beverage produced from natural sources is contaminated by artificial products the resulting compound is not so useful nor digestible. For instance, wine which is made partially from sugar and beer made partially from dextrose, although they may be healthful and wholesome beverages, are inferior in quality and character to the real product made from grape juice or barley malt.

=Buttermilk.=--The residue left in the churn in the manufacture of butter is termed buttermilk. There are two distinct varieties of buttermilk, namely, that resulting from the churning of unsoured cream and that remaining from the churning of soured and ripened cream. The first kind of buttermilk does not differ in its characteristic essentials from skimmed milk and therefore is not considered here. The second class of buttermilk is far more common and is a beverage of pleasing acid taste. When made from properly ripened cream it is wholesome and delicious, especially in summer time. Its composition is that of cream subjected to enzymic action during the ripening process by which an agreeable degree of acidity is produced due to lactic acid, together with the incidental changes which take place in the composition of other parts of the liquid due to enzymic action. Buttermilk also usually contains small particles of butter itself which escape aggregation during the final process of churning. In well prepared buttermilk, however, these particles of butter are not very numerous and they add nothing to the palatability, although they do add something to the nutritive properties of the beverage. The buttermilk represents that portion of milk which is one of the chief constituents of cream as far as bulk is concerned, freed practically from its butter fat. It does not differ greatly, therefore, in its chemical properties from skimmed milk, although there is a slight difference in the relative percentages of the milk solids in cream as compared with the same constituents in whole milk. The composition of buttermilk is shown in the following table:

COMPOSITION OF BUTTERMILK.

FROM SWEET FROM SOUR CREAM. CREAM. _Percent._ _Percent._ Water, 89.74 90.93 Fat, 1.21 0.31 Milk sugar, 4.98 4.58 Protein, 3.28 3.37 Ash, 0.79 0.81 Acidity, ... 0.80

=Bonnyclabber.=--Bonnyclabber is a term applied to milk which has become soured by lactic fermentation, producing a gelatinous coagulation of casein which is sufficiently firm at times to prevent the liquid from being poured. Clabber may be regarded as a natural cheese curd except that the fat is chiefly on top. It is a beverage or food of a very agreeable taste to most persons and is often eaten with sugar. In the summer it is often formed during hot murky weather, especially of that character which produces thunder storms. For this reason it is a common supposition that thunder or lightning sours milk. The thunder and lightning, however, have nothing to do with this process. The condition of the atmosphere which produces an environment favorable to electrical disturbances of this kind also favors in the highest degree the growth of the organisms which produce the lactic ferments. Hence thunder storms and the rapid souring of milk are frequently coincident leading to the popular impression as above mentioned. Inasmuch as the souring of milk usually takes place after the cream has risen the composition of clabber is practically that of skimmed milk modified by the lactic fermentation which has taken place.

BUTTER.

When cream, especially cream in which incipient lactic fermentation has been set up, is subjected to agitation in a churn under proper conditions of temperature the particles of butter therein contained are collected into masses so that the butter can be separated from the residual liquid. This process is technically called churning. The domestic churn in its simplest form is perhaps well known to almost everyone, especially those who have lived in the country. In the domestic manufacture of butter the cream is collected and set aside until sour, that is, until lactic fermentation has set up. When this is sufficiently advanced the cream is placed in a churn, the simplest form of which is a wooden, cylindrical vessel of appropriate size, being much longer than its horizontal diameter. The churn is provided with a dasher, namely a perforated wooden disk with a handle which passes through a hole in the cover. When the churn is charged the butter is produced by agitation with the dasher. In winter time warm water is added to the mixture in order to raise the temperature to the proper gathering point of butter, namely 65 to 70 degrees F. For the same reason cold water is added in the summer time. The art of the dairy maid is shown in the proper regulation of the temperature to secure the best results. When the cream is properly ripened and the temperature is suitable the gathering of butter will be accomplished in from twelve to thirty minutes. In unfavorable conditions the duration of churning may be for a much longer period.

In dairies and large establishments churning is accomplished by machinery with very different mechanical appliances, but the principle which underlies the process is the same as those outlined above. The accompanying figures illustrate the process of churning by mechanical means in a modern dairy (Figs. 20 and 21).

=Treatment of Butter.=--The crude butter secured by churning is subjected to washing and seasoning processes in order to prepare it for the market. The washing or working of butter is accomplished by means of water. The object of this “working” is to separate from the crude butter as much of the curd and other non-fatty constituents of the cream as can be conveniently accomplished. The removal of these mechanical particles not only makes a butter of a higher grade but also one of better keeping qualities. The working of butter also has much to do with its grain or texture, which is one of the characters of butter to which great attention must be paid. The best grade of butter and that which brings the highest price in the market is that which receives no treatment other than that of the washing and working process to which attention has been called. This kind of butter is known as natural or unsalted or uncolored butter, that is, a fresh, sweet product of an agreeable aroma, palatable, of fine texture and grain, and is the best product of its kind for human consumption. It also brings the highest price on the market and, by reason of its method of preparation, the consumer can usually be assured that it is fresh in character.

=Salting Butter.=--In the United States, especially, consumers of butter generally require that it shall be salted. For this purpose fine grades of dairy salt are used as free as possible from impurities and consisting of fine particles or crystals which rapidly dissolve in the residual moisture of butter. This promotes a uniform distribution of the salt in the form of brine throughout the mass of butter. The existence in butter of undissolved particles of salt is highly prejudicial to its taste and character. The quantity of salt used in butter is determined by the taste of the consumer. The more salt the butter contains the less value it is as butter and hence the quantity should be limited to the smallest possible amount demanded by the consumer’s taste. Often butters are found in commerce which are so full of salt as to be wholly unpalatable and there is a tendency on the part of the greedy manufacturer to add excessive quantities of salt because it is very much cheaper than the butter itself and thus he hopes to add to the profit of the industry. On the contrary this practice usually results in loss, since such highly salted butter naturally brings the lowest price. The amount of salt which is used in butter should not exceed two percent.

It is a common supposition that salt in butter is a preservative. This is true when used in large quantities, that is, in quantities which render the butter somewhat unpalatable. The very small quantity of salt used purely for condimental purposes cannot be regarded as aiding in any material way the preservation of the product.

=Coloring Butter.=--Unfortunately the practice of artificially coloring butter is very prevalent in the United States. Practically all the butter found upon the market, even in the spring and summer, is more or less artificially colored, often with coal tar (anilin) dyes which, to say the least harm of them possible, are open to suspicion in respect of wholesomeness. The practice of coloring butter produced in winter may be regarded as universal, though none the less reprehensible on that account. The object of coloring butter is, undoubtedly, to make it appear in the eyes of the consumer better than it really is, and to this extent can only be regarded as an attempt to deceive. If cows are properly fed during the winter months with wholesome, nutritious food to which a small proportion of roots such as carrots or ruta bagas are added or with yellow maize and clover hay, even in winter time the butter produced will have an attractive light amber tint which appeals strongly to the æsthetic sense of the consumer. The natural tint of butter is as much more attractive than the artificial as any natural color is superior to the artificial. There is the same difference between the natural tint of butter and the artificial as there is between the natural rose of the cheek and its painted substitute. It is claimed, and perhaps justly, that the use of certain vegetable colors, such as annotto, does not introduce any unwholesome substance into the product. Admitting this, we must next ask whether it deceives the consumer. If so, it is difficult to understand upon what ethical principal any plea for the artificial coloring of butter can rest. If it is admitted that there is no valid reason why butter should be colored other than the artificial coloring of foods in general, which is a practice so reprehensible that it is almost universally denounced, its practice cannot be easily defended. The dairymen of our country are honest and honorable and evidently do not clearly see the false position in which the practice of coloring butter puts them. When the dairymen of our country understand that the naturally colored products will bring the highest price on the market and appeal more strongly to the confidence of the consumer it is believed the artificial coloring in butter will be relegated to the scrap pile of useless processes. It cannot be claimed in any sense that coloring of butter artificially ever adds anything to its value as a nutritive substance.

One of the claims for justifying the coloring of butter is that it distinguishes it from oleomargarine. This, however, is not the case since, under the law, oleomargarine may be colored upon the payment of a tax of ten cents per pound. The consumer has at his disposition a complete protection against fraud in the use of oleomargarine by the operation of state and federal laws, irrespective of the tint of the product. Oleomargarine and butter are distinguished from each other by their natural colors and also by their chemical and physical properties and, therefore, there can be no justification for the coloring of butter on the plea that it distinguishes it from oleomargarine. Thus, from every point of view it is evident that the artificial coloring of butter is undesirable. It interferes with the right of the consumer, who should know the exact character of the product he buys, and it stands in the way of the prosperity of the manufacturer by keeping upon the market a cheaper product which tends to decrease the price even of that of better quality.

=Standard Butter.=--According to the standard established by Congress butter must contain more than 16 percent water and not less than 82.5 butter fat.

=Renovated Butter.=--The law of Congress which controls the manufacture of renovated butter is executed jointly by the Treasury and Agricultural Departments. The quantity of renovated butter produced during the year ending June 30, 1905, was 60,290,421 pounds.

=Adulterated Butter.=--The quantity of adulterated butter which was produced under the authority of the Act regulating the manufacture of oleomargarine and butter and on which is laid a tax of 10 cents per pound during the fiscal year ending June 30, 1905, was 3,671 pounds. These data show that the tax of 10 cents per pound laid upon adulterated butter has practically destroyed the manufacture of that article. Normal butter has from 12 to 14 percent of water. It is sometimes rechurned with water to raise the water content to 16 percent. Such a practice results in adulteration whether the content of water exceeds 16 percent or not.

=Influence of Food upon Butter.=--The character of butter is very easily affected by the nature of the food consumed by the cow. Butter has the faculty of absorbing very readily odors of all kinds. Foods, therefore, which have characteristic odors impart them to the butter. A most striking instance of this is in the eating of wild garlic. In this case both the milk and the butter are affected to such a degree as to be in many cases unpalatable. Hence foods or substances in foods which are aromatic or odoriferous are likely to impart their peculiar odor to the milk, cream, and butter. Of all the constituents of milk the fat appears to have the highest faculty of absorbing these objectionable odors. Therefore, the feeding of distillery slops is also apt to impart an unpleasant odor to milk and butter, whereas if these slops be dried and their volatile aromatic principle expelled little discomfort is experienced in their use. The physical characteristics of butter are also changed in a marked degree by the character of the food. Butter fat, as has already been indicated, is distinguished from other animal fats by its content of soluble and volatile acids of which butyric is the chief. There are certain kinds of foods which decrease or tend to decrease the content of butyric acid in butter.

=Influence on Melting Point.=--The character of the food also has a marked influence upon the melting point of butter. The author showed many years ago that the use of cottonseed meal as food for cows tends to raise the melting point of butter. This was regarded as an index of some value for the southern portion of the country, where a high temperature obtains over a period of six or seven months of the year. If the melting point of butter, which when normal is about 33 degrees C. (91° F.), could be increased to 35 or 36 degrees C. (95° F.), it would be of immense advantage in these warm climates and, in fact, in all parts of the country during the months of July, August, and September. There is no apparent tendency to increase the melting point of butter by feeding other oil cakes.

=Transmission of Other Principles in the Food to the Butter.=--Experience has shown that when cows are fed cottonseed meal or its products the quality of cottonseed oil which responds to the color test known as the Halphen test, namely, the production of a red color with carbon disulfid and amyl alcohol, is transmitted also to the butter. In some cases this reaction is extremely faint while in others it is displayed with an intensity which is claimed by some to be equal to that of the admixture of 5 percent of cottonseed oil with the butter. The use of cottonseed meal, on the contrary, does not seem to notably affect either the content of volatile acid in the butter nor its refractometer reading. (Experimental Station Record, Volume 25, Page 716.)

OLEOMARGARINE.

Oleomargarine is the name applied to any fatty substance which is prepared to be used in the same manner as butter. Oleomargarine is defined by Act of Congress as follows:

An Act defining butter, also imposing a tax upon and regulating the manufacture, sale, importation, and exportation of oleomargarine. (Approved August 2, 1886.)

“That for the purposes of this act certain manufactured substances, certain extracts, and certain mixtures and compounds, including such mixtures and compounds with butter, shall be known and designated as “oleomargarine,” namely: All substances heretofore known as oleomargarine, oleo, oleomargarine oil, butterine, lardine, suine, and neutral; all mixtures and compounds of oleomargarine, oleo, oleomargarine oil, butterine, lardine, suine, and neutral; all lard extracts and tallow extracts; and all mixtures and compounds of tallow, beef fat, suet, lard, lard oil, vegetable oil, annotto, and other coloring matter, intestinal fat, and offal fat made in imitation or semblance of butter, or, when so made, calculated or intended to be sold as butter or for butter.”

The manufacture of oleomargarine can only take place in the United States under the supervision of officials of the Internal Revenue. All oleomargarine which is artificially colored a yellow or yellowish tint in semblance of natural butter pays an internal revenue tax of 10 cents per pound. Oleomargarine uncolored pays a revenue tax of one-fourth cent per pound. Oleomargarine when made under proper sanitary conditions from sanitary raw materials is a wholesome and nutritious article of diet and usually can be sold at a smaller price than butter. It is especially a food product which commends itself to those who are under the necessity of practising strict economy in the cost of food in the family. The principal objection, and in fact the only valid objection, to its use is found in the frauds which have been committed in its manufacture and sale. There has been a constant disposition on the part of dishonest manufacturers and dealers, since the time when oleomargarine became a commercial commodity, to sell it as butter. Although the penalties of national and state laws are very severe in this respect the practice is continued. The opportunity for gain is so great that the cupidity of the manufacturer overcomes his fear of punishment and disgrace. With a more rigid national and state inspection, it is reasonable to hope that this fraudulent use of oleomargarine can be avoided and the pure, unadulterated article under its own name be supplied to those who prefer it either on account of its properties or its price.

=Materials Used in the Manufacture of Oleomargarine.=--_Neutral Lard._--One of the principal basic components of oleomargarine is neutral lard or lard stearin, the properties of which have already been described. Beef fat stearin is another basic ingredient of oleomargarine and is the stearin derived from tallow or tallow itself. Beef fat has a higher melting point than lard and beef fat stearin a still higher melting point than the tallow. Hence it forms an ideal ingredient with which to mix the oily components which enter so largely into the manufacture of oleomargarine. The beef fat or beef fat stearin is easily distinguished by means of the microscope. It forms beautiful radiated fan-like crystals, the characteristic appearance of which is shown in Fig. 9, page 67.

_Cottonseed Oil and Cottonseed Oil Stearin._--These are also important ingredients of oleomargarine affording the oily or more liquid constituents which, when mixed with the lard and stearin above mentioned, form a compound the melting point of which is slightly above that of butter and sufficient to maintain it in an unmelted state even in warm weather. The quantities in which these different ingredients are used vary greatly in different manufacturing establishments and depend largely upon the location where the oleomargarine is to be used. When manufactured for tropical or subtropical regions larger quantities of stearin are employed than when used in temperate zones or for winter consumption, in which case larger quantities of cottonseed oil and cottonseed oil stearin are employed with the mixture. After the fats are mixed it is usually the practice to churn them with milk in order to give a flavor of butter to the product. In some cases the yolk of eggs is mixed with oleomargarine, as it is claimed that they impart thereto a firmer and more homogeneous structure which renders the mass better, especially for cooking purposes. All the ingredients which are used in the manufacture of oleomargarine are made known and recorded in the books of the Commissioner of Internal Revenue and thus it is a product which it may be said is strictly under government supervision.

=Description of Process of Manufacture.=--The fat is taken from the cattle in the process of slaughtering, and after thorough washing is placed in a bath of clean, cold water, and surrounded with ice, where it is allowed to remain until all animal heat has been removed. It is then cut into small pieces by machinery and cooked at a temperature of about 150 degrees until the fat, in liquid form, has separated from the fibrine or tissue, then settled until it is perfectly clear. Then it is drawn into graining vats and allowed to stand a day, when it is ready for the presses. The pressing extracts the stearin, leaving the remaining product, which is commercially known as oleo oil, which, when churned with cream or milk or both and with or without a proportion of creamery butter, the whole being properly salted, gives the well-known food-product, oleomargarine.

=Adulteration of Oleomargarine.=--Since the coloring of oleomargarine is permitted upon the payment of a tax, oleomargarine which is colored cannot be said to be adulterated when the tax has been paid, although if coloring were not a legalized operation it would be an adulteration. Yellow oleomargarine is an imitation of natural butter and its manufacture should be prohibited unless the product is marked “imitation.” The character of the coloring materials used is not prescribed by the Commissioner of Internal Revenue but as a rule the coal tar dyes are preferred in the coloring of oleomargarine to the vegetable coloring matter such as annotto and saffron. The remarks which have been made in connection with the use of poisonous materials in other products apply to oleomargarine.

_Adulteration with Egg Yolks._--An adulteration which has been practiced in this country is the admixture of preserved egg yolks. Usually these yolks are secured in China, broken, and placed in vessels and preserved with borax or boric acid or salt. These eggs are generally collected during the early spring and summer months and are not sent to the United States until the fall or winter. The importation of such articles is now prohibited under the food laws of the country so that the adulterations with the imported article is no longer to be feared. It is possible to preserve domestic eggs in the same way, and the use of them in this manner is regarded as an adulteration, since such preserved egg products cannot be regarded as suitable for human food.

_Adulteration with Preservatives._--Fortunately preservatives are not used to any extent in the manufacture of oleomargarine when intended for domestic use. The most suitable preservative in such a case as this would be borax or boric acid. It is not believed that these preservatives are used to any extent when the product is intended for domestic consumption. Whether or not preservatives are used in the product sent abroad I am unable to say.

=Production of Oleomargarine.=--According to the report of the Commissioner of Internal Revenue the quantity of oleomargarine taxed at 10 cents a pound produced in the United States for the fiscal year ending June 30, 1905, was 5,584,684 pounds, and for 1906, 4,888,968 pounds. The quantity produced in 1906 taxed at one-fourth cent a pound was 50,545,914 pounds.

COMPOSITION OF OLEOMARGARINE.

SOL. SOL. SPECIFIC IN- ACID BY ACID BY GRAVITY SOLUBLE WASHING DISTIL- ALBU- AT 40°C. WATER. ACID. OUT. LATION. SALT. MINOIDS. .90490 9.34 93.59 0.12 0.25 3.64 0.35

From the above data it is seen that the objections to the use of oleomargarine are more on the grounds of fraud and deception than in regard to nutritive and dietetic value. The components used in the manufacture of oleomargarine, when properly made, are all wholesome and digestible materials such as are consumed in eating various food products. It does not appear, therefore, that any valid objection can be made against the use of oleomargarine from a physiological or hygienic standpoint.

CHEESE.

=Historical.=--The preparation of cheese is one of the oldest of the technical processes. It appears that it was known during the time of King David, at least a thousand years before Christ, and the Greeks were acquainted with it before the writings of Homer. Aristotoles and Hypocrates describe the curdling of milk which at that time appears to have been accomplished by the use of the juice of the fig. The use of cheese was very common in Rome in the earlier historical days but the most of it was imported from the North. Cæsar speaks of the preparation of cheese among the German tribes. Cheese must, therefore, be regarded as one of the very oldest forms of prepared food used by man. It probably is almost, if not quite, as old as wine. These historical facts are interesting in showing how from the earliest times man has made use of the natural ferments to prepare food from the raw material. Attention must be called in this connection to the fact that many people claim that such foods as these are not natural foods but wholly artificial. The fallacy of such a claim is not difficult to show. An artificial food is one which is prepared out of materials which, themselves, are not edible food products or, at least, are not digestible or of a character which does not naturally occur by ordinary processes. Artificial foods, therefore, are purely synthetic, that is, made up from the elemental substances, or they are mixtures or compounds. On the contrary a food like cheese or wine is not a mixture or compound but a natural product from materials which themselves are food products. Milk is the raw material of cheese as the must of the grape is of wine. Both milk and must are rich and nutritious foods. The changes which each undergoes are in many respects the same. The must of wine undergoes an alcoholic fermentation and the milk sugar of cheese is subjected to a lactic fermentation and its casein to a proteolytic change which materially alters its character.

Cheese products are a very important part of food materials of the dairy. The term cheese is applied to the solid product produced from milk by coagulation of the casein with rennet or lactic acid and subjecting the solid product thus produced to a process of fermentation and ripening by the addition of appropriate seed material, seasoning, and storage at convenient temperature for varying periods of time. In the precipitation of the casein of milk the fat particles become mechanically entangled and form a part of the precipitate. There is a certain quantity of other milk constituents incorporated in the form of water, milk sugar, and mineral matter in the precipitated mass. The greater part of the other bodies which the milk contains, consisting of the milk sugar and a considerable portion of the soluble mineral matter, are separated in the form of whey. The composition of fresh cheese is that of that part of the milk which is precipitated and which is entangled mechanically in the precipitated matter. The ripened cheese is changed in its chemical constituents mostly as the result of fermentative action upon its nitrogenous constituents, that is, the casein, albumin, etc., contained therein. The ferments tend to change the casein into a more soluble form of protein, while at the same time they develop a flavor and aroma in a way agreeable to the nostril and palate. Various forms of moulds and other organisms grow on and in cheeses which influence their palatability and character. The final product of the ripened cheese varies not only with the nature of the original material as determined by the milk itself but with the character of the preparation and the nature of the organisms and ferments which are active during the ripening period, and also with the time and temperature of storage.

=Kinds of Cheese.=--It is not necessary and perhaps it would be impossible to attempt an enumeration of all the various kinds of cheese which are offered on the market. The first classification of cheese depends upon the character of the milk used. The term “cheese” in this country naturally refers to a product made from cow’s milk since that is the principal milk used in the United States for cheese making. The term is used in this manual in that sense and when there is no qualifying word employed it is always understood that the product in question is made from the cow’s milk. This implies that the milk is at least a standard milk, that is, a whole milk, unskimmed and containing not less than 3.25 percent of butter fat. According to the definition fixed by the Congress of the United States the term cheese is applied not only to this product but also to one containing a larger percentage of fat than this. The term cheese applies both to cheese made from milk and cheese made partially from milk and partially from cream. The term “full cream cheese” is also often used in the trade but is likely to be misleading and deceptive. The real significance of the term full cream cheese is that it is made of whole milk or milk unskimmed which contains its full complement of cream. The term “cream cheese” is also often used to indicate a cheese made partially of milk and cream. It is evident that the term cream cheese in this sense is misleading, since it can be properly applied only to a cheese made from cream alone. Such cheeses are made but, inasmuch as cream must have not less than 18 percent of fat in order to be called cream according to the United States standard, the cheeses made from such a source are too oily and fatty for ordinary consumption.

=Cheese Made from Goat’s Milk.=--Goat’s milk is also frequently used in making cheese. It is extensively employed in France and Switzerland for cheese making and also in other parts of Europe, and to a limited extent in this country. Some of the varieties of cheese which are most highly prized are made from goat’s milk, such as Roquefort.

=Adulteration and Misbranding of Cheese.=--The most common form of adulteration or sophistication of cheese is the misbranding thereof in respect of the country where made or in respect of character. This is a form of deception which has long been established in the trade and one which cannot be condoned or excused. There are certain varieties of cheese whose names should be respected and in fact, in the case of all varieties that have an established character and reputation, their name should not be applied to other articles made in imitation thereof. In this country there is a national law which prohibits the marking of a food or dairy product falsely as to the state or territory where made. For instance, a cheese made in Ohio cannot be marked New York cheese and peaches grown in Delaware cannot be marked California peaches, maple sirup made in Indiana cannot be labeled Vermont maple sirup, etc. The ethical principle underlying this law is one which will meet the approbation of every well meaning man and therefore the extending of this principle to other forms of misbranding is an easy step. If it is a violation of the law to mark a cheese made in Ohio as made in New York it is certainly a violation of the ethical principle underlying that law to name a cheese made in Connecticut Cammerbert. Unhappily, however, there are cheeses made in the United States to which foreign names are given, the universal excuse being that they are cheeses of the same type. In many cases this excuse is not a valid one and in no case is it an accepted one. To name a cheese made from cow’s milk the same as that made from ewe’s milk is a distinct misbranding in every sense of the term. There should be no difficulty in established varieties of cheese made in this country having names which are not deceptive and not intended to mislead the consumer as to the state, territory, or country where made. In one sense all cheese may be said to be of the same type, but because the taste and odor of a cheese made in the United States imitates to some extent that of a cheese made in France is no excuse for giving the French name to the American product. A further illustration of this principle is found in the following: The term Roquefort, for instance, is not properly applied to any cheese product except that which is made at or in the vicinity of Roquefort. In no other part of France can cheese be made bearing the name of Roquefort. The use of the term Roquefort, therefore, in any way upon American cheese is a misbranding and an attempt to deceive which usually is successful. There is not so great an objection to the term Swiss cheese as to Roquefort, but there is the same kind of an objection. The cheese which bears the name of Schweitzer-Käse is very extensively manufactured in Germany and sold under that name. A similar cheese is also extensively made in this country and sold under the name of Schweitzer-Käse. In this case there is no particular location or place which originated the name and has the sole right to use the name Swiss cheese. It is the name of a whole country and not of a location, and yet it is evident that Swiss cheese properly can only be made in Switzerland and not in Germany or in the United States. Any hard, tough cheese in which a large number of holes is found and which on cutting makes a flexible, semi-leathery slice has to a certain extent the appearance and perhaps the taste and flavor of genuine Swiss cheese.

It should not be difficult to find a market for all good cheese made in this country, under appropriate American names indicating their origin. If the term Swiss cheese is at all allowable on a package it should be placed as a minor part of the label and with the statement that it is of that type. Even this transgression is perhaps difficult of excuse.

=Artificial Coloring.=--Next to misbranding and misnaming of cheeses, perhaps the most common adulteration is that of artificial coloring. The public taste has been led in the matter of cheeses, especially of American origin, to look for a deep yellow color. This is also associated with the idea of the use of a large quantity of rich, naturally yellow-colored cream. The addition of an artificial color to a cheese never adds anything to its value, and to the really æsthetic eye detracts much from its appearance. The presence of this rich artificial tint is calculated in many instances to excite a suspicion in regard to the character of the cheese and thus interferes with its proper gustation. There is another more serious objection than the one just mentioned, namely, that it is possible from skimmed milk to make a highly colored cheese which would appear to the consumer to be made of whole milk or of milk and cream, and thus a deliberate deception is perpetrated. The consumer of cheese should demand that artificial coloring of all kinds be omitted from cheese products.

Moreover, these colors may of themselves be deleterious in character and there is no restriction, so far as I know, at this time in the United States to prevent a manufacturer, if he so desires or through his ignorance of the use of coloring materials of a poisonous character, from using any amount.[22] The coal tar dyes are cheaper and produce faster and more natural looking tints than the vegetable colors such as annotto and saffron, and hence, unless they are prohibited by law, they are almost universally employed. All of these dyes in a concentrated form are highly poisonous and injurious and several instances are on record of death, especially in the case of young children, from eating concentrated colors. The fact that a poison of this kind is diluted by the cheese is no excuse for its use. The only protection which the consumer has, which is reliable in all cases, is the prohibition of coloring matter in cheese.

[22] Written before the passage of the food-bill.

By Act of Congress of June 6, 1896, coloring matter is permitted to be used in cheese in the United States and doubtless it will continue to be used under this authority until that portion of the Act is repealed or until the consumer demands an uncolored article. The pure, natural color of the cheese is universally acknowledged to be best, most palatable, and most desirable.

=Preservatives.=--Fortunately there is little to be said in regard to preservatives in cheese because they are almost unknown. The addition of a preservative to a cheese at the time of its production would so seriously interfere with the ripening process as to defeat the purpose of storage altogether. Hence in so far as preservatives are concerned there is little danger of adulteration.

=Impure Raw Materials.=--If cheese be made of standard milk as provided for by the commissioners it must be made of pure, wholesome material. On the contrary, inasmuch as there is no official inspection of cheese factories, it is entirely possible through carelessness, ignorance, or design to use in the making of cheese milk which may itself be infected. Cheese made from such milk of course would carry the infection of the milk. This is a sort of adulteration which can only be excluded by careful sanitary inspection of cheese factories.

=Filled Cheese.=--Formerly there was a very considerable adulteration of cheese by manufacturing it from skimmed milk and supplying from an artificial source the necessary fat. Cottonseed oil, lard, and other edible oils are used for this purpose.

_Composition of Filled Cheese_ (Circular No. 11, Bureau of Animal Industry).--Neutral lard is the principal fat which is substituted for milk fat in filled cheese. It is used to the extent of two or three pounds for every 100 pounds of skimmed milk. The principal objection to a filled cheese is not on account of its containing lard, which in itself is not unwholesome. But lard is an entirely different fat from milk fat, and differs in the character of the fermentation which takes place. The characteristic flavors and odors which are contributed by the milk fat in the cheese are entirely wanting, and the cheese is devoid of aroma and flavor and is nothing more than a mixture of casein with lard. Filled cheese is such a poor imitation of the genuine article that it can never have any very great vogue, and especially under the present law which requires it to be labeled and the payment of a tax. The law relating to filled cheese is found in the appendix.

A filled cheese which is on the market not properly stamped and duty paid in harmony with this Act of Congress is adulterated, and they who make and sell it are amenable to the law. The annual report of the Commissioner of Internal Revenue for the year ending June 30, 1905, shows that no receipts were obtained by the tax on filled cheese during that year. If any was made it was made surreptitiously and in defiance of the law.

From the above data it is seen that the manufacture and sale of filled cheese in the United States is almost a thing of the past and this form of adulteration, assuming that the law is thoroughly executed, is not now likely to be often met with.

=Cottage Cheese.=--Cottage cheese is a term applied to a product which is usually only a raw material of cheese. It is the fresh, precipitated, and unripe milk product, above described as used in cheese making. It is a highly nutritious and very palatable product, usually prepared at home and not suitable for keeping or transportation. It is often made from sour milk in which the casein is coagulated by the natural development of lactic acid. The sour milk is placed in a cloth bag and the whey allowed to escape by gravitation. The final portion of the whey may be forced out by pressure. The residue, when properly seasoned with salt or in any way to suit the taste of the consumer, is very palatable. Cream is often added to this residue which increases the normal amount of fat which it contains.

COMPARATIVE COMPOSITION OF AMERICAN AND EDAM CHEESE.

The chemical composition of some of the principal varieties of cheese are shown in the following table:

WATER. ASH. FAT. PROTEIN. Percent. Percent. Percent. Percent.

American cheese, 27.5 4.1 32.5 28.38 Edam cheese, 36.34 4.24 31.17 22.28

The data show that cheese is essentially a nitrogenous and fat food, containing only small quantities of carbohydrates, and therefore it is not a complete ration. It is a ration, however, which is complementary to a highly starchy diet such as rice or maize bread or potatoes. Bread and cheese or potatoes and cheese or rice and cheese, therefore, make a well balanced diet, highly nutritious, easily digestible, and quite palatable.

=Manufacture of American Cheeses.=--The large cheeses which are principally found upon the American market may be said, in general, to resemble the Cheddar type, although the calling of these cheeses by the name “Cheddar” is misleading, and to that extent a misbranding of the product.

There are two common methods of making these cheeses which are in vogue in the United States, namely, the “stirred curd” or “granular” method and, second, the Cheddar method. (Bulletin 104, Department of Agriculture of Pennsylvania, 1902.) The latter one is the more extensively used. The second product does not differ essentially in character from the first, though the latter method, it is claimed, gives a more solid cheese and one of more uniform character and with a slightly less content of moisture. Since the Cheddar method has practically come into sole use, displacing the first method, a description of the Cheddar method alone will be sufficient to illustrate the method of making large cheeses which are now so common on the American market and which have such a well merited reputation. The process is divided into eight parts: First, coagulating the milk; second, cutting the curd; third, heating the curd; fourth, removing the whey; fifth, cheddaring the curd; sixth, milling the curd; seventh, salting and pressing the curd; eighth, curing the cheese.

_Rennet._--As has been said in the description of cheese making, the material which is most useful in the precipitation of the curd is rennet. The rennet is the secretion of the stomach of various animals, that of the calf being most highly priced for cheese making. The fourth stomach of the animal is the one which is used in the manufacture of rennet. The aqueous extract made from these stomachs contains a ferment which has the property of coagulating casein in a very high degree. One part of good rennet preparation from healthy stomachs of calves will coagulate 1000 parts of milk. In former days rennet was freshly made and used at the factories. At the present time it is largely prepared on a commercial scale and sold to the cheese maker. It is highly important that the rennet used in cheese making should be of the best quality, as an inferior grade gives a bad taste and color to the cheese. Just as in the manufacture of fermented beverages and making of bread the character of the yeast is a dominant factor in the nature of the finished product, so it is even to a greater degree in the case of rennet. Those who purchase the rennet already made should therefore be certain it is of a quality to give the desired character to the cheese. The greater the amount of milk fat in milk the larger the proportion of rennet, since the milk fat protects to some extent the casein from the action of the ferment. Experience has shown also that during the summer the rennet acts more readily upon the milk, probably due to the higher temperature. Care should be taken to avoid the use of any excess of rennet, since anything more than the amount necessary to conduct the coagulation is apt to add an unpleasant flavor to the cheese. The curd also in such cases is less cohesive and makes a tougher and drier product which does not lend itself so readily to the ripening process. For this reason the rennet which is to be used should always be tested in small quantities of milk beforehand in order that the proper proportion to be used may be known so that the process in a large way may be conducted with certainty and not by guess. (“British Dairy Farming,” by Jas. Long.)

Rennet is sometimes treated with borax to preserve it during transit. In such cases the borax may not all be removed by the whey and is consequently found in ripened cheese. Its introduction in this way should be avoided.

_Coagulating the Milk by Rennet Extract._--This process is often termed by the cheese makers “setting the milk with rennet.” The milk which is used for the purpose of cheese making should be, in the technical language of the cheese maker, “ripe,” that is, containing a sufficient quantity of lactic acid. The principal method of producing the proper amount of lactic acid in milk is by keeping it warm, namely, at a temperature of about 84 degrees. At this temperature the most favorable conditions exist in milk for the rapid growth of the lactic acid ferments. If the natural ferments which produce lactic acid are not in sufficient quantity in the original milk it is better, rather than to wait too long a time, to start the development of the lactic acid by adding an artificial ferment. Lactic ferments are specially prepared for this purpose, or some previously ripened milk may be added to the mass. This is called a “starter.” From two to five pounds of “starter” are usually required for each one hundred pounds of milk. The degree of ripening is ascertained by measuring the quantity of lactic acid present. The proper condition of the milk is tested by means of a rennet preparation and if the milk will coagulate, when thus tested, in about one minute or a little more it is an indication that a sufficient amount of acid has been developed to add the rennet for the proper coagulation of the milk. It is important to have the milk in just the right condition in order that the proper operations in cheese making may go on uniformly. Care must be taken, however, not to have too much lactic acid in the milk. For instance, 0.2 of one percent is too great, and such a milk is very liable to give trouble in subsequent operations. In the curding of milk by rennet the temperature should be kept between 82 and 86 degrees. The amount of rennet extract, of course, varies with its character and strength, and this is best determined by the cheese maker’s experimenting in order that the proper quantity to be added to the great mass of milk may be known beforehand. A sufficient quantity of rennet extract should be used to curdle the milk in fifteen or twenty minutes for a quick-curing cheese, and in thirty to forty minutes for a slow-curing cheese. The rennet extracts in common use are added at the rate of from one-half to five ounces for 1000 pounds of milk. Before adding, the extract should be diluted with from 20 to 40 times its volume of water at a temperature of from 85 to 90 degrees. The rennet thus diluted acts with uniformity on the milk, preventing the production of curd of a lumpy character. Previous to adding the rennet extract the mass of milk is thoroughly stirred in order to mix the fat therewith and the dilute rennet added evenly and slowly with constant stirring which is continued for several minutes. A gentle stirring of the surface of the milk should be continued until the curd is at least half formed, in order that the fat may not separate. After the stirring is finished, a cloth is placed over the top of the vat to keep the surface of the milk from cooling, and the milk is then left undisturbed until the coagulation is complete. The coagulation goes on gradually until the whole mass of milk is one solid coagulum produced by the changing of casein into paracasein.

_Cutting the Curd._--In order that the whey may be separated it is necessary that the curd be cut into pieces. The smaller the pieces of curd, the more rapidly will the whey escape. As soon as the curd is formed it shows a tendency to contract and this tends to force out the whey. By cutting the extent of the surface from which the whey can exude is amplified and the rapidity of the process is enormously increased. The time at which the curd is to be cut is one of great importance and is determined by the skill and experience of the cheese maker. If the curd is cut when it is too soft there may be large loss of fat and a decreased yield of cheese. If the curd is too hard the whey is more difficultly removed and the quality of the cheeses is not so fine. The following test is used to determine when the curd is in the right condition to cut. The end of the index finger is inserted obliquely into the curd half an inch or more and then slowly raised toward the surface. If the curd breaks apart with a clean fracture without leaving any particles on the finger and the whey which exudes from the broken surface is clear and not milky it shows the proper time has come for cutting. Specially devised knives are used for cutting the curd, which leave it in small cubes of about one-half inch surface. Skill in the use of the cutting knife is important and can only be acquired by proper experience.

_Heating the Curd._--As soon as the curd is cut the whey begins to go out of it and the curd settles to the bottom of the vat, the whey being of a higher specific gravity than the curd. After the pieces of curd sink to the bottom the surface easily reunites and, when broken apart, additional fat is lost. As soon, therefore, as the curd is cut the whole mass is kept in gentle motion by hand stirring or with a wire basket designed for the purpose, care being taken to avoid breaking or comminuting the cubes. When properly stirred the whey appears clear and is free of small particles of curd.

The curd contracts and hardens during this process, and soon reaches a condition when the surface does not adhere so readily. The vat should be kept warm during the process of separation of the whey, the temperature being raised to about 90 degrees and finally, toward the last, to 98 degrees, about blood heat.

_Separating the Curd._--The precipitated curd is left in contact with the whey for some time, and during this period some of the lactic acid in the whey unites with the paracasein. The setting of the curd is finished when a small mass which has been squeezed in the hand to remove the whey is pressed against a bar of iron heated to little short of redness, and it is found that there is left, adhering to the iron, fine silky threads. These threads are formed by the compound of lactic acid and paracasein, and the more of this compound there is the longer will the strings be. When the curd shows by the hot iron test strings one-eighth inch long it is an index that the time has arrived for the separation of the curd from the whey.

_Gathering the Curd._--After the whey is removed the cubes of curd are left in the bottom of the vat until they mat or pack together, a process which is technically known as cheddaring. The curd is sometimes removed from the vat and placed on a special apparatus for this purpose called a curd-sink. When the curd has matted together, forming a solid mass, it is cut into blocks 8 × 8 × 12 inches. These blocks are turned in the vat in order to facilitate the removal of more whey. The blocks of curd are carefully placed, one over the other until they form a large mass.

The process of solidifying or cheddaring accomplishes two purposes:

First, the whey is expelled to a considerable extent and, second, the lactic acid unites with more of the curd, changing not only its chemical composition but also its physical state from a spongy, tough, rubber-like consistence, with a high water content, to a mass having a smooth, velvety appearance and feeling, and a soft, somewhat plastic consistency.

_Milling the Curd._--This process consists in cutting the lumps of curd into small pieces in order to introduce the salt and to handle it more readily when it is to be placed into hoops for pressing. This process is done by special mills which avoid, in so far as possible, the loss of fat.

_Salting and Pressing._--Salt is added for several purposes, chiefly for flavoring, but it also has other uses. It aids in removing the whey,--it hardens the curd and it checks or retards the formation of lactic acid. Excessive salting, however, is injurious. From 2¹⁄₂ to 3 pounds of salt should be added to the curd made from 1000 pounds of milk. Before putting in the press the curd is cooled to a temperature of about 80 degrees, and after putting into the mold it is subjected to pressure to give it a proper form, rather than to remove the whey which is practically all gone by this time. If the whey has not been properly removed before the cheese goes into the press it is almost impossible to get it out then. The pressure should be uniform and continued for at least twenty-four hours. If a screw is used the pressure should be light at first and gradually increased. After the cheese has been in the press about an hour it is removed, turned, a cloth adjusted about it, and the entire surface wiped carefully with a cloth wrung out of hot water.

The sizes in which American cheeses are made depends largely upon the market, the more common size being 15 inches in diameter, and the cheese weighs from 60 to 65 pounds. There is also a very large manufacture of cheese seven inches in diameter, known as “Young Americas” and weighing only from 8 to 10 pounds.

_Curing._--The higher the temperature to which cheese is exposed in curing the more rapid the curing process will take place, but the poorer the quality of the cheese. Experience has shown that a low temperature, 55 degrees F. or even less, gives much better results, although it requires a greater length of time. If cured at a higher temperature the fat is apt to exude, and will not be evenly distributed in the cheese. It is, therefore, more profitable, as well as better for the consumer, to cure at low temperatures, producing a superior quality with less loss of moisture and a cheese which sells for a better price.

_Moisture in the Curing Cellar._--The cellar in which the curing takes place should contain air with a proper degree of moisture. The relative percentage of moisture in the air as compared with the total amount which it can hold should be from 65 to 75. This is determined by placing in the curing room a hygrometer which registers the degree of saturation.

=Qualities of American Cheese.=--The quality of cheeses is judged by (1) flavor, (2) body, (3) texture, (4) color, and (5) general appearance. In regard to flavor it is impossible to describe what is meant. Only the connoisseur can determine properly whether a cheese has a flavor which is sound, healthy, and indicative of the highest quality. The cheese flavor should be free from any admixture of other flavors. Cheese resembles butter in this respect, that it absorbs and then gives off foreign flavors with great facility. Therefore in the whole process of cheese making care must be exercised to exclude every odor or flavor of an undesirable character from the cheese house.

_Flavor._--Under flavor also may be described taste, which should be of that biting, incisive character due to proper development of ripening and its attendant bacterial and enzymic products. The various foreign flavors in cheese may be due to the odor of cows or the stable or may suggest “rotten eggs,” or it may be the flavor of rancid butter due to the decomposition of butter fat in the cheese.

_Body._--This is also a term which it is difficult to define. An American cheese is said to have a perfect body when it is solid, firm, and smooth in substance. This quality is ascertained by pressing the cheese between the fingers. When it does not press down evenly between the finger and thumb it is said technically to be “corky.” It is smooth when it feels velvety-like and is not harsh or gritty.

_Texture._--The term texture applied to American cheese refers mainly to its compactness. It is nearly related to body. The texture may be fine and close or porous. The texture is perfect when a cut surface of the inside of the cheese presents to the eye a solid, compact, continuous appearance, free from breaks, holes, or lumps. Cheese should not show any visible or separated moisture or fat. The texture of American cheese should be smooth, free from breaks, and fairly hard. The bandage should be smooth and neat, extending over the edge on each end of the cheese about two inches.

_Color._--A true and unadulterated cheese should have only the color of the milk from which it is made, and any other color incident to ripening which is usually green. Unfortunately cheeses of American origin are often artificially colored. An over-deep yellowish or reddish tint, therefore, should be regarded as a mark of inferiority. Artificially colored cheese should not rank as high on the market as that of a natural tint, which is much more pleasing to the eye and much less objectionable to the æsthetic taste. Color is often added to conceal inferiority in the milk used.

The sides of the cheese should be straight and of uniform height all around.

The following scale of points is used in judging cheese, according to the above qualities: Flavor, 45 to 50; texture, 30 to 35; color, 10 to 15; general appearance, 5 to 15.

=Cream Cheese.=--This is a soft cheese which is rapidly growing in popularity. It is made from rich milk or milk and cream mixed together. It resembles in general Neufchatel, but it is richer in butter fat and is put up in a different form. The temperature of the room in which the cheese is made is quite important. It should be kept as nearly as possible at 75 degrees. The milk is first warmed to 70 degrees and run through a separator by means of which the cream is taken out, together with one-half the volume of milk. This makes either dilute cream or very rich milk, as you may choose to call it. The cream is heated to 84 degrees and about four or five ounces of rennet extract added per thousand pounds. The rennet is carefully and gradually stirred into the mixture, using about fifteen minutes for the addition. The mass is then allowed to remain at rest until whey is seen around the sides. The whey is then removed by draining, the resulting curd pressed and mixed with about 3 percent of salt. The cheese is not subjected to a curing process. It is molded into flat, thin cakes about 3 by 4 inches, wrapped in parchment paper, and in this condition packed for shipment.

=Manufacture of Foreign Types of Cheese in the United States.=--The improvement of cheeses made in the United States by securing different forms of ferments and utilizing the best method of setting, pressing the curd, and ripening used in other countries is worthy of all encouragement. Unfortunately a disposition has arisen in our country of giving the names of foreign varieties to the domestic articles. Many fancy domestic cheeses are sold under strictly foreign names such as Cheddar, Stilton, Cheshire, Schweitzer, Limburger, Camembert, Brie, Roquefort, etc. In fact there seems to be no limitation upon the adoption of a name already identified with a distinct type and locality. Such a tendency is greatly to be regretted and perhaps it is only necessary to point out to our people the ethical offense which they are committing by such practices to secure their discontinuance. It is, however, a perfectly legitimate undertaking to import the ferments which produce the famous cheeses of the world and utilize them to the fullest extent in cheeses of American origin. This, however, should be done in such a way as to carefully avoid applying the name of the original article to the domestic product. Perhaps it would be no ethical offense or no very great offense to place upon the labels of the cheese products a statement that they are of the same type as the foreign product they imitate. This, however, should be an explanatory phrase and not a part of the label which attracts principal attention. It is far better that a manufacturer should adopt some local name which would become identified with his product, and thus become a valuable trade-mark. The attempt to pass domestic cheese under foreign names is an offense against good ethics and also against the law. It is nothing more nor less than misbranding, and cannot be justified even in the absence of a law forbidding it.

_Success with Foreign Ferments._--Considerable success has attended the introduction of the foreign processes into the United States, together with the ferments which produce the cheeses abroad. The environment, however, cannot be imported and therefore the ferments may rapidly assimilate different properties under changed conditions, and the continued importation of fresh ferments may be necessary to preserve the type of cheese. Some of the principal types of foreign cheeses made in the United States are those which are mentioned above. A particularly excellent study has been made of the process of making a Camembert type of cheese in this country. (Bureau of Animal Industry, Bulletin 71, 1905.) This particular cheese is a type of Camembert which is made at the Storrs Agricultural Experiment Station of Connecticut. For these experiments a cheese maker familiar with the Camembert manufacture in France was secured. The method of making the cheese and also of separating the curd and ripening was as nearly as possible like that used in France. The style of the packages was the same, so that from external appearances it would be quite difficult to distinguish them from the genuine Camembert cheese of France. The success attending these experiments shows that it is possible to improve domestic cheeses by scientific effort in the direction of using the proper ferments. These soft cheeses made in Connecticut were of good quality and had something of the flavor and type of the Camembert itself, though it was not difficult for even a novice to distinguish the two varieties from one another.

These studies above referred to have resulted in a marked degree of progress in the knowledge of the real changes which take place in the ripening of cheeses. The officials in charge of the work differ somewhat with the author in respect to the character of the product, claiming that the making of Camembert cheese is not dependent upon uniform conditions obtained only in certain localities but rather on securing the proper cultures and conditions which are possible almost anywhere. The fact of the case is that the cheeses made at the Connecticut station are probably made under much more scientific conditions and much more rigid control than the real Camembert cheese made in France. The success which attended these efforts is only a proof of the statement made above that the introduction of these processes for making fancy cheeses in this country will doubtless result in the development of types of American origin of peculiar flavor and quality. Such cheeses when properly named and not confused with those of foreign origin will become quite as familiar and well known, both at home and abroad. (Bureau of Animal Industry, Bulletin 82, 1906.)

=Sage Cheese.=--The consumption of the variety of cheese known as sage cheese is not very large at the present time in the United States and is restricted to certain localities, yet it is rapidly growing in favor. Consumers who are accustomed to it are willing to pay a larger price for it than for ordinary cheese. Sage cheese is made exactly in the same manner as that described for the manufacture of Cheddar. The flavor of sage is imparted in three different ways, first, by adding the sage extract or tea to the milk; second, by adding the extract to the curd before salting; third, by adding the sage leaves to the curd before salting. The latter method is found to be the most satisfactory requiring the least amount of sage to give any definite flavor. Three ounces of sage leaves are found to be sufficient to flavor the curd from 1000 pounds of milk. The stems and impurities of the sage leaves are carefully removed and the leaves ground to a fine powder before mixing with the curd (Michigan Board of Agriculture, 1904).

=Principal Cheeses of England.=--The principal English cheeses are Stilton, Cheshire, Cheddar, double and single, Gloucester, Derby, and Leicester. According to Dr. Voelcker, the finest flavored cheese is Cheshire, which differs from any other in being made from milk which is perfectly sweet, and some authors think its peculiar aroma is due to this fact. On the contrary, the more general opinion is that the best cheeses are made from milk slightly sour rather than that which is perfectly sweet.

Cheshire cheese is manufactured by mixing the evening milk, which is kept cool over night, with the morning milk, and then warming the mixture until the temperature is about 90 degrees. The proper quantity of rennet is added and when the cheese is to be extremely yellow also some annotto. After thoroughly mixing, the mass is left for nearly an hour, by which time the coagulation is completed. The next operation is the breaking down or cutting up of the fresh curd, and this is an important process. Upon the care which is exercised in doing this depends in a large measure the richness and quality of the finished product. When properly manipulated the whey which is separated will be of a greenish color and clear, while the proper combination of milk fat and casein which is secured in separating the whey will make a cheese of first class quality. The curd is so dense as to naturally separate from the whey by deposition, and the latter is thus drawn off by a stopcock properly placed in the vat. The curd is then placed upon a cloth stretched over lattice work in order that the separation of the whey may be complete. Finally before passing to the cheese house the curd is treated with eight ounces of salt to twenty pounds of curd. After the cheese is molded it is placed in a warm room for one or two days, and then taken to the press house where it is subjected to the usual pressure. The pressing process is continued by wrapping the cheese in dry cloths and subjecting to new pressure every day for five or six days. The cheese is then removed to the ripening cellar where it is turned two or three times a week. It is ripe and ready for consumption in less than one year. There are a great many variations from this method of making Cheshire cheese, but they all follow the same general plan.

_Manufacture of Cheddar Cheese._--The cheese is made in various parts of England though chiefly in Somerset, the period of manufacture extending from April to November. Cheddar cheeses are made in large sizes varying from 60 to 100 pounds each. The temperature of precipitation for Cheddar cheese is somewhat less than for the Cheshire cheese, being about 80 degrees. Rennet is used solely in the coagulation, lactic acid not being liked for that purpose. In the making of Cheddar often some of the fat escapes in the whey and this is afterwards collected and made into butter. Two pounds of salt to 100 pounds of curd are used.

_Derby cheese_ is a name applied to cheese made in Derby. The Cheddar system of making it is usually employed.

_Gloster cheeses_ are made on the same plan as that of the Derby and do not need any further description.

_Leicester cheese_ is a variety of cheese which is very popular and made chiefly in the county of Leicester. The coagulation of Leicester cheese is made at a little lower temperature than that previously described, varying from 76 to 84 degrees. The curd is allowed to stand for about one-half hour before it is broken up and the whey separated. The best manufacturers of cheese disapprove of the use of artificial coloring and it may be said that eventually it is pretty certain that all cheese makers will come to the same conclusion. The use of coloring matter in cheese, even of annotto, adds nothing to its richness, and tends to deceive the customer into thinking that the milk employed was richer in cream than it really was. The Leicester cheeses are small in size compared with Cheddar. About eleven pounds of milk are used to make an ordinary cheese.

_Stilton cheese_ is probably the most familiar and highly prized of all English varieties. It is not always to be obtained, and many imitations of Stilton are made and bear its name. The name it bears is from the name of the town where it was first, and is now, made. It is a cheese which has been known for about a century and a quarter. It is principally made between March and September and solely from the milk of cows fed on natural pasture, that is, for the finest variety. The use of artificial food for the cows is at once detected in a change for the worse in the character of the cheese. At first the rennet employed was made from the stomachs of lambs instead of cows and in the olden times the cheeses were not considered to be sufficiently mellow and ripe until they were two years old and exhibited spots of green in the interior.

The most approved modern process of manufacture is mixing the morning and evening milk and bringing it to a temperature of 79 degrees. Rennet is then added and the mass allowed to stand for about an hour and a half. The curd is removed into cloths set in frames for the purpose of allowing the whey to separate. Usually about an hour is allowed for the natural separation. The cloths are then tightened and brought closer together to produce slight pressure and placed in a cheese tub, several of them together, where they are allowed to remain for twelve hours. Usually a longer time is allowed before the curd is cut up. The salt is added in proportion of one pound to 60 pounds of fresh curd. The curd is then placed in tin cylinders with perforated sides, the cylinder being 12 inches deep and 12 inches in diameter, and put in a room at about 65 degrees to favor the separation of the whey which requires from six to seven days. The cheeses are then removed from the cylinders, brought into proper shape by a knife and wrapped with strong cotton cloth and allowed to remain for twelve days longer when they are removed to the drying room and kept at 65 degrees. During this process the original curd placed in the cell loses about one-half its weight so that ten pounds of curd in the end make five pounds of cheese. A very common method also is to make cheese twice a day from morning milk and evening milk separately. Extra cream is often added in making Stilton cheese, only whole milk or milk and added cream being used. The principal point to be considered with curing is the regulation of the temperature.

Other varieties of cheese which are known in England are mostly named from the localities where they are produced and partake in general of the character of cheeses already described. These are Lancastershire, Wensleydale, skimmed milk cheese, butter milk cheese, potato cheese, and various forms of soft cheese or those used without being allowed to ripen for any length of time.

=Varieties of Cheese Made in France.=--There is a general idea that France is pre-eminently a cheese making country and this is true in so far as the making of certain brands of cheese which have international reputations is concerned. France, however, according to statistics, imports a larger quantity of cheese than she exports though probably the value of her exports is greater than the imports because of the high character and price of the exported articles.

_Manufacture of Camembert._--The first cheese of this variety was made in 1791 by Marie Fontaine on a farm in the community of Camembert, near Vimontiers. The period of manufacture of Camembert cheese extends from March to September. It is made from whole cow’s milk from which none of the cream has been extracted. The rennet is added at the temperature at which the milk comes from the cow as nearly as possible and the milk is artificially heated, the morning and evening milk being mixed, to this temperature. After the addition of rennet the milk is gently stirred for two or three minutes, a wooden cover placed over the pan, and left for five or six hours. The curd is sufficiently set when touched with the finger it does not adhere thereto. The curd is removed from the pan by a spoon and put into cylindrical metal molds open at the end and from these molds the whey is allowed to escape. It requires about two liters of milk to make one cheese. The whey is allowed to drain for about two days. After that time the mold is turned, a little fine white salt placed upon the top and allowed to drain for another day. After about 48 hours the cheeses are taken from the molds and salted. They are then placed in the drying room upon racks covered with straw. The drying room must be well ventilated and the air which is blown in for ventilation must be strained to be free of dust and insects. Care is taken also to exclude the sunlight, as this is very injurious to the proper development and ripening of cheese. The cheese remains in the dryer from 20 to 25 days. The ripening cellar is the next point to which the cheese is removed, and this cellar is kept as nearly as possible at 50 degrees F. The cheeses remain in the ripening cellar about 30 days, during which time they are frequently turned and carefully watched. The progress of the fermentation which takes place in the cheese is indicated by its appearance. In modern times the manufacture of Camembert cheese is continued practically throughout the whole year, but the artificially ripened cheese, that is, made during the winter by the aid of artificial heat, does not compare in quality with the product which is naturally ripened during the summer months. The manufacture of Camembert cheese has extended to a considerable distance from the original village, but it is all made in that part of France.

_Emmenthaler Cheese._--Emmenthaler cheese is a variety of Swiss cheese of the same type as Gruyère. It is sometimes called the “cart-wheel” cheese on account of its immense size. These cheeses are sometimes three or four feet in diameter and of a disk-like shape, something like a wooden wheel sawed out of a round tree. It is a cheese which was originally made in Switzerland, although the manufacture of it has spread over into that part of France bordering Switzerland. It has the general character of Swiss cheese in texture, also in composition and nutritive value.

_Brie Cheese._--This is one of the most famous of French cheeses. It is made in the form of a round flat mass about 16 inches in diameter for the grande Brie and 12 inches in diameter for the petite Brie. The thickness of the cheese is about one inch. The method of preparation is not very greatly different from that of cheeses in general. During the curing process, as in the case of Camembert, mould develops, especially on the outside of the cheese, and the change which goes on in the interior breaks down the casein, forming a creamy mass of a strong, piquant flavor. The mould which grows upon the outside of Brie cheese gives it a strong odor which reminds one of decomposition. Brie cheese might be said to resemble in general properties the Camembert variety of cheese.

_Roquefort_ cheese is a very popular cheese made in France from sheep’s milk. When properly ripened it shows a green mould. It is made in a particular way at Roquefort, and according to König has the following composition:

Water, 36.85 percent Fat, 30.61 „ Proteids, 25.25 „ Lactic acid, 1.90 „ Ash, 5.39 „

_Port Du Salut._--This variety of cheese has a most deserving popularity, not only upon the Continent but in the United States. It is, however, not so generally known in this country as the Roquefort and Camembert varieties. It was long manufactured by a secret process by the Trappist monks of Bricquebec in the Department of Manche.

The secret of the manufacture of this variety of cheese is guarded with the same jealousy by the monks as is the secret of making the chartreuse liqueur. Port Du Salut is always put up in very small packages of cylindrical form, flat, and about one inch in thickness. The cheese has a number of holes, in which it resembles the Swiss cheese. Its flesh, however, is mellow, and does not have the toughness nor solidity which characterizes the flesh of Swiss cheese. Although the monks’ secret has been well guarded the general method of its manufacture has been described (“Cheese and Cheese Making,” by Jas. Long and John Benson). The milk is brought to a temperature of 86 degrees F., and is treated with rennet in such a way as to separate the curd in about one-half hour. The separation of whey is secured in the usual manner, first, by allowing broken curd to stand, and afterwards by pressure. A peculiar form of pressure is said to be used by the monks,--a number of screws are placed side by side on a beam and a number of cheeses may be pressed at the same time. The pressure is applied solely by the hands and so is not very severe. After pressure the cheeses are placed in a ripening cellar, which is kept at about 54 degrees F. Care is taken in the ripening that the cheese does not become too dry.

_Pont L’Evêque_ cheese is well known upon the Continent, especially in France where it is made. It takes its name from the village where the manufacture is carried on, which is not very far from Havre. The cheese is usually put up in a square or oblong package about one inch in thickness and of a size weighing about one pound. It has a tough crust and may be kept for some time after it is ripe with safety. The milk is set at a temperature of 88 degrees and a sufficient amount of rennet added to produce precipitation of the curd in about fifteen minutes.

When the curd is stiff enough to be cut and removed it is placed upon a mat made of rye straw through which the whey is allowed to filter. As the whey runs off the curd becomes tougher and the mat is brought together in such a way as to exert gentle pressure. This separation of the whey is continued until the curd can be placed in metal molds which vary in size according to the size of the intended cheeses. The cheese is ripened at a temperature of about 58 degrees in a humid cellar so as not to lose too much water.

_Gervais_ cheese belongs strictly to the family of fancy cheese, being made of a mixture of milk and cream. It is produced in large quantities in France and finds almost an exclusive domestic market. It is named for its manufacturer, M. Gervais. The mixture is set at a very low temperature, about 65 degrees. The rennet which is used is diluted with water and added in small quantities so that the curd does not separate for eight or ten hours. The whey is separated in a cloth bag and under very gentle pressure. The cheeses are usually sold in only a partially ripe state and the cheese combines the flavor of both cheese and cream.

_Bondon_ cheese is another cheese which is made largely in the region of Rouen. The size of the cheese is usually very small, from seven to nine being made from a gallon of milk. The method of manufacture is more like that of Gervais and differs from it chiefly in being made solely from milk instead of a mixture of milk and cream.

_Limburger Cheese._--Limburger cheese is one of the most famous of the different varieties of foreign cheese, chiefly because of its bad odor. This odor is due to specific forms of ferments introduced during the ripening process. Generally Limburger cheese is made from pure milk, but occasionally skimmed or partially skimmed milk is used. The milk is set at rather a high temperature, from 92 to 100 degrees. After the coagulation has taken place the curd is broken into pieces the size of a hen’s egg and allowed to settle to the bottom of the kettle as the whey separates. In England a copper kettle is usually employed for the testing vessel. After the whey has separated the curd is taken out and placed in rectangular molds with perforated bottoms, then laid on tables so that the remaining portion of the whey may drain off. The molds are turned from time to time to promote the separation of the whey and to make the cheeses keep their form. The cheeses are next placed in rows on a flat table with thin pieces of boards between them and subjected to light pressure. During this time they are salted by applying salt externally and rubbing the surface at frequent intervals for three or four days. The salt dissolves and permeates the mass. During the salting and pressing the cheeses are kept at a uniform temperature of about 60 degrees. The curing takes place in cellars, well ventilated but very moist, at a temperature of about 60 degrees. As the cheeses ripen they grow soft. The curd takes on its characteristic greasy appearance at the time of the ripening, becoming, at first, a yellow and then a reddish yellow. The softening begins on the outside and proceeds toward the center and the cheese is considered to be marketable when one-fourth of it has taken on its characteristic texture. The softening of Limburger cheese is due to a ferment which breaks down into a soft mass the casein or paracasein of which the cheese is largely composed. By using the same kind of ferments and by following the same process, imitations of Limburger cheese are made in the United States and other countries. These imitations, however, never equal the original in the character of the product nor in flavor or taste, and should not bear the name of the real article.

COMPOSITION OF LIMBURGER CHEESE.

Water, 35.7 percent Fat, 34.2 „ Casein products, 24.2 „ Milk sugar and undetermined, 3.0 „ Ash, 2.9 „

Limburger cheese was first made in the Province of Lüttick in Belgium. It has, however, come to be considered chiefly as of German production. The chief cause of the putrefactive fermentation which takes place in Limburger cheese is the extremely moist condition in which it is kept. For this purpose the atmosphere of the ripening cellar should be almost saturated with aqueous vapor, containing at least 95 percent of its maximum degree of saturation. This moist atmosphere, together with the low temperature at which the curing takes place, keeps the cheese soft and promotes the putrifactive ferments. Under these conditions the surface soon begins to get shiny and soft and changes from white to a reddish yellow. This change makes its way to the center, converting the harsh curd to a soft condition. The time required for this softening of the cheese is from four to six weeks. (“Cheese Making,” by John W. Decker.)

_Edam Cheese._--Edam cheese is one of the most famous of the cheeses of Holland. It is made at the town of Edam, situated on the Zuyder Zee, about twelve miles northeast of Amsterdam. The milk from which Edam cheese is made should be properly acidified as has already been described. The coagulation takes place and the curd is separated much in the same manner as is used in the manufacture of Cheddar cheese. The curd is held for a time in the vat in a granular condition in order to develop greater acidity and until it will string one-half inch or one inch on the hot iron already described. It is then ready for the mold. The molds are of such a character as to give the cheese a spherical shape about six inches in diameter. Each cheese weighs about four pounds. It has a perfectly solid texture and its flavor is something like that of old Cheddar, except that it is a little more salty and somewhat harder. It is cured at a temperature of about 60 degrees and at a humidity of about 80 degrees. The curing period is somewhat longer than for most cheeses, lasting about eight or ten months and even a year. A slow curing is particularly necessary in the production of Edam cheese.

_Coating with Paraffine._--In the curing of cheese sometimes it is coated with paraffine to avoid loss of weight. Coating with paraffine does not necessarily interfere with the character of the cheese, though it is probable that it must interfere in some way with the normal ferments. Paraffine is wholly indigestible and may produce injurious effects if swallowed with the cheese. (“Farmers’ Bulletins,” Nos. 186-190.)

=Fancy Cheeses.=--There is a large number of cheeses made in which cream enters as a prominent part. It is difficult to give these any particular name and the term “fancy cheese” has been applied to this form of cheese as a whole. They are usually put up in small packages or little pots and thus form an article of diet quite distinct from the large press cheese of commerce. In fact they are intended more for condimental purposes and to be eaten in something of the same manner as butter rather than cheese. These cheeses usually are sold for a much higher price and, therefore, can be regarded more as a luxury than as a regular article of diet.

It might be well to mention some of the more particular varieties of these fancy cheeses.

_Gruyère._--Gruyère is a cheese made in Switzerland, where it is much prized and from where it is sent to the various parts of the world. It is a pressed cheese and is rather of a larger size than the fancy cheeses already described, and it is difficult to say whether or not it should find a place among them.

_Parmesan._--Parmesan is a variety of cheese made in Italy. It is about the same size as Gruyère and thus has an intermediate place between the large pressed cheeses of commerce and the fancy cheeses above mentioned.

_Gorgonzola_ cheese is a very familiar cheese made in Italy and belongs to the same class as the two preceding ones. It is in one sense a fancy cheese and yet is made in such quantities as to belong rather to the commercial variety.

=Bacterial Activity in Cheese.=--Modern science has led to the conclusion that the ripening of cheese is due principally to bacterial activity. The changes which take place in the chemical and physical properties of cheese materials, the flavor and aroma which are developed, the production of mould and other growths are marks of the activity of organisms of different character, living and unorganized. Due credit must be given to the enzymic (unorganized) action in these processes and the enzymes are not regarded as living organisms but, on the other hand, as catalytic agents inducing chemical changes similar to those produced in starch by the action of diastase. The peculiar flavors of cheeses which are found in different kinds have been ascribed in late years almost exclusively to the character of bacterial activity. This assumption is perhaps correct, but it must not be forgotten in this connection that the same species of bacteria, in changed environments, does not always produce the same results. The activities of bacteria are peculiarly sensitive to the environment, such as change of temperature, physical conditions of different kinds, locality, and other factors of a complex nature, making up the total conditions in which the organisms live. For this reason the attempts to produce peculiar cheeses which belong in particular localities in other localities have not been gustatorily even if technically successful. It is true that cheeses may be made of the types mentioned, having some of the general characteristics but lacking that indescribable something which after all gives true character. Just as it is impossible to make a Rhine wine in California or a Bordeaux wine in New York so is it impossible to make a Cheddar cheese in Ohio or a Camembert cheese in Connecticut.

=Number of Bacteria.=--The number of bacteria, per gram, which appear in cheese varies according to the age of the cheese, conditions under which it is made, temperature, etc. The usual number of bacteria in one gram of cheese varies from five hundred thousand to nearly one hundred million (21st Annual Report of the Wisconsin Agricultural Experiment Station).

Ageing does not seem to increase the number of organisms, since it has been found by some observers that the maximum number present in cheese is found at the time it is taken from the press. It is difficult also to properly sample a cheese for the number of bacteria, since they are unequally distributed in different parts thereof, and the trier, by means of which the sample is secured, may show largely differing numbers in different parts of the same cheese. During the process of curing, especially if the curing be at a high temperature, the number of organisms decreases. At first the decrease is very rapid and then becomes slower as the cheese becomes riper. The decrease in the number of bacteria when the temperature of curing is raised is somewhat contrary to expectations. It has been found that when a cheese is taken from cold storage, say at 24 degrees F., and placed in a temperature of 60 degrees F., the decline in the number of bacteria is always greater than when the cheese is retained at the lower temperature. This may be due to the fact that bacteria which have been developed at a low may lose their vitality at a higher temperature. On the contrary, the development of flavor does not seem to depend upon the number of organisms since the peculiar flavor of cheese is more rapidly developed at the higher temperature, provided it be not too high, although this be attended with a diminution in the number of organisms. Evidently the conditions which favor the metabolic activities of organisms also favor their destruction, since when they have performed their functions they undergo natural disintegration. The character of cheese is such that when it is once formed there is no more opportunity given for a rapid proliferation of the organisms.

It may be found, however, that the development of bacterial life is not the sole or perhaps not the dominant factor in the development of flavors and aromas in cheeses but that this process is due very largely to the enzymic activities obtained from the rennet and which pre-exist in the milk.

=Chemical Changes Which Take Place During the Ripening of the Cheese.=--_Loss of Weight._--During the process of ripening of cheese there is considerable loss of weight, amounting to from 15 to 20 percent of the total weight of the fresh product. This loss is due chiefly to the evaporation of water, while in the fermentation which takes place volatile bodies are formed which also escape with the water. For instance, any free gas, either carbon dioxid, hydrogen, or nitrogen, which is produced will escape, likewise any alcohol which is formed will at least partially volatilize. There may be also a slight loss due to mechanical attrition, but that is not of any consequence. Owing to the loss of water some of the constituents which may diminish in actual quantity have their percentages proportionately increased. These changes are illustrated by the following analytical data:

MILK WATER. PROTEIN. FAT. SUGAR. ASH. Fresh cheese, 40.42 24.80 28 1.65 5.43 In the dry substance, .... 41.62 46.99 .... .... Same cheese one year old, 33.12 27.35 31.70 2.96 4.87 In the dry substance, .... 40.89 47.40 .... ....

The quantity of water which is lost in part depends upon the temperature of the store house and the dryness of the air. The loss of water should not be too great, otherwise the cheese would be dry and the ripening process would not go on in a proper manner. In some of the processes which take place during the ripening of cheese water is formed. If, therefore, there is no loss of weight during the process of ripening, the ripened cheese would have more water than the fresh cheese and this would impair the quality of the product. The loss of a certain part of water, namely, from 15 to 20 percent must be regarded as an advantage in the production of cheese.

_Changes in the Protein._--The most important chemical changes, from a digestive point of view, which take place in the cheese are those which the protein undergoes. This protein substance consists chiefly of casein and undergoes profound alteration due to enzymic action during the process of ripening. The casein which when dry naturally forms a leathery, tough material changes into a more soluble and softer product, and during this change there are produced aromas and flavors which add much to the value of the cheese for edible purposes.

The character of the coagulation of the cheese originally has much to do with the general changes which the product undergoes during fermentation. The cheese makers for this reason must pay special attention to the rennet which they employ in the production of the precipitate. One of the most important of the changes which the casein undergoes is that which results in the production of ammonia. This indicates a complete decomposition of the protein substance, at least in part, so that the total amount of protein which is lost as such may reach as high as 25 or 30 percent of that present in the original cheese. There are also produced notable quantities of lucin and other nitrogenous compounds soluble in alcohol. In general it may be said that the changes in the nitrogen constituents of cheese are extremely helpful to digestion. Not only is the protein of ripened cheese more soluble but even the parts which remain unchanged as far as the protein constituent is concerned are so affected by the action of fermentation as to render them more readily subject to the action of the digestive ferments in the alimentary canal. There is a popular superstition that the use of cheese at the end of a meal helps to digest the other food which has given rise to the adage “Cheese, thou mighty elf, digesting all things but thyself.” There is a base of scientific truth in this expression since in ripe cheese the enzymes remain still in an active form and when taken into the stomach must necessarily exercise an influence of considerable magnitude upon the process of digestion. The custom, therefore, which is so universal, of finishing a dinner with a bit of cheese is evidently based upon sound physiological as well as gastronomical principles.

_Changes in the Fat._--The chemical changes which the fat undergoes in the process of ripening the cheese are also of considerable importance. It is claimed by some authors that additional fat is produced from the casein during the process of ripening, which is the cause of the lardy appearance of some cheeses. Many observers have found in ripened cheese a larger percentage of fat than that which was noticed in the fresh cheese. This apparent increase, however, may be due to analytical error, since in the fresh cheese the fat becomes entangled with highly insoluble caseous matter and is difficult of extraction, whereas after the ripening of the cheese and degradation and breaking up of the caseous tissues the fat is much more readily extracted. While it is not impossible that fat should be formed by the fermentation of the casein it does not seem that it is probable.

In examinations which were made of fresh and ripened cheese of the variety known as Roquefort there was found in the dry substance of the fresh cheese 40.80 percent of protein and 53.91 percent of fat. In the same cheese after it was quite old there was found in the dry substance 37.78 percent of protein and 56.14 percent of fat. These data serve to bear out the theory that fat is formed from the protein. On the contrary, it must be remembered that in the fermentation of the protein a number of volatile bodies are formed, especially ammonia, and thus the diminution in the percentage of protein is probably due to the loss of volatile bodies, and the increase in the quantity of fat is therefore a relative one, probably, and not absolute. There is no doubt, however, of the fact that the quantity or character of the fat does change considerably during the process of ripening. There is no reason for supposing that the fat alone of all the contents of cheese escapes enzymic action. It is profoundly changed in its character by the fermentations to which it is subjected, and this change, while it unsuits the fat for butter, may probably make it more palatable and desirable in cheese.

=Digestibility of Cheese.=--Reference has already been made to the fact that in the ripening of cheese the protein of the milk, consisting principally of casein, undergoes certain changes which apparently, at least, increase its digestibility. I use the word “apparent” because the flavor and aromas which are produced in the ripening of a cheese act as condimental substances and thus naturally excite the glands which secrete the digestive enzymes to greater activity. Therefore the increased digestibility may be due in part to the increased activity of the digestive ferments as above described rather than to the changes in the casein itself. It must be admitted, however, that these changes during ripening tend to make the casein more granular, softer, and to convert it into compounds more easily acted upon, and are thus favorable to increased digestibility. Experimental studies have shown that in a well ripened American cheese of the Cheddar type 93 percent of the protein present in the cheese and 95 percent of the fat are digested. Artificial digestion experiments have also shown that the pancreas ferments have much more effect upon cheese digestion than the peptic, showing that the cheese is more acted upon in the small intestines, perhaps, than in the stomach. Attention must also be paid to idiosyncrasies in these cases, as there are many people who find it impossible to digest cheese in any form. The eating of larger quantities than are necessary also tends to derange the digestive organs. A well ripened cheese, therefore, should be eaten rather as a condimental substance than as an actual food product, though its value as a food is fully attested. (“Farmers’ Bulletin,” No. 162.)

=Effect of Cold Storage on the Curing of Cheese.=--Attention has been called, in the description of different methods of making varieties of cheeses, to the ordinary temperature at which cheeses are cured. In European countries these temperatures are maintained without the use of artificial means. In the United States it is difficult to maintain a very low temperature in summer time without the use of artificial refrigerators. Experimental studies have determined that when the temperature of ripening or storage is reduced to a considerable extent below that usually specified for the standard varieties of cheese the quality of the cheese is superior although the time for storage or ripening is very much prolonged. The artificial curing of cheese has been secured at as low a temperature as 40 degrees. There is also a less loss of weight in cheese cured at this low temperature. A cheese which was cured at 40 degrees when examined by experts scored a mark of 92.4 while the same cheese ripened at 60 degrees scored 95. Another test of a cheese cured at 40 degrees scored 95.7 while the same cheese cured at 50 degrees was marked 94.2 and the cheese cured at 60 degrees 91.7.

=Preparations of Casein.=--Properly in connection with cheese preparations may be mentioned those products which are of a food value, procured from casein itself. The precipitated casein is prepared for the market by washing, drying, and grinding to a fine powder, and is then sometimes called protein flour. Sanose is a mixture consisting of about 80 percent of casein and 20 percent of the protein derived from the white of egg. The addition of the white of egg enables the casein to remain in suspension when mixed with water and thus causes the preparation to resemble milk. Casein preparations of this form are practically insoluble in water and, therefore, are not perhaps of the best forms of nitrogenous food for invalids. To avoid this insolubility the casein has been combined with alkalies and the preparations are known as _nutrose_ and _eucasein_. Plasma is also a preparation of casein with alkalies which are added in sufficient quantities to give 7 percent of ash. These caseinates, as they are sometimes called, that is, combinations of casein with alkalies, are soluble in water and are found to be to a certain extent digestible and nutritive preparations. Casumen and sanatogen are other preparations of casein with alkalies or glycero-phosphate. Wonderful claims are made by manufacturers concerning the digestibility and nutritive properties of these preparations. It is doubtful, however, if they have much greater value, if any, than natural casein in the form of milk or as ripened in cheese. Preparations of this kind usually appeal strongly to those who suffer from digestive disorders and therefore high-sounding names, which are given to practically the same preparations, lead the seeker after health often to try the same substance under a dozen different appellations. These remarks are not made for the purpose of decrying in any way the merits which these preparations may have but only to illustrate a very marked tendency on the part of many people to attribute extreme virtues to ordinary food substances which are sold under attractive and sometimes deceptive names and whose properties and virtues are advertised in an expert manner. Because a food substance consists almost wholly of pure protein is no indication whatever of its exceptionally high food value. Protein is only one form of food and a concentrated ration of protein in any of these forms is just as likely to do harm as good. For emergency rations, for economy in transportation, and for certain diseased conditions of the digestive organs these preparations are undoubtedly valuable, but they have little claim upon the general public in a state of health as staple articles of diet. They are much more nutritive than the extracts of beef and other meats which have obtained a vogue wholly out of proportion to their dietetic or medicinal value. (“Foods and Principles of Dietetics,” by Robert Hutchinson.)