PRESERVED MEATS.
Meats which cannot be eaten at the time of or soon after slaughter are necessarily preserved until the time of consumption. It is difficult to draw a definite line between a preserved and a fresh meat. A general distinction is the following: Fresh meat is meat which is prepared for consumption without the use of any condiment or preservative, without sterilization, and with none of the artificial methods of keeping, except cleanliness and a low temperature.
The above definition, as will be seen, covers meat placed in cold storage. A special distinction, however, must be made in this case between meat placed in cold storage for the purpose of transportation only and meat placed in cold storage to be kept for an indefinite time. Where meats are prepared for consumption by slaughter and appropriate dressing and shipped long distances to the consumer the cold storage car, ship, and warehouse become a necessity. There is some reasonable limit for keeping such products, beyond which they should be differentiated from fresh meats. Whenever meats are kept in cold storage so long as to afford the opportunity for the growth of a mould, or undergo other changes of a chemical or physical character which distinguish them from the fresh products, they should be placed in a different class. Fresh meats may, therefore, be divided as follows:
Class I. Meats intended for immediate consumption and passed to the consumer within, at the most, one week after slaughter. Class II. Cold storage meats, which are placed in refrigerators, frozen, and kept for a longer period than one week. There is evidently also a limit to the length of time which meat should remain in cold storage, no matter how low the temperature may be, since the action of organisms which produce decay cannot be entirely overcome. The exact limit at which frozen meats can be kept without becoming inedible has not been determined. Without this determination, however, it is advisable that such limit should not be approached. Inasmuch as the supply of fresh meat is practically uniform, or can be made so by the dealer therein, there seems no good reason for the storage of meat in refrigerator compartments for a longer time than is necessary for transportation and a reasonable time thereafter for passing into consumption, except in cases of emergency. It might be safe to say that no meat should be kept in a cold storage warehouse longer than a month after its reception. Numerous instances might be cited in which meat may be kept for a much longer time, but the question for the consumer is not how long a while meats can be kept but how soon they can be placed in his hands. In this connection it should not be forgotten that it is the opinion of perhaps the majority of hygienists and connoisseurs that fresh meat, especially beef, improves for a certain length of time in cold storage. It is probable that the fresh beef which is served to the people of the United States is on an average a month old, and is said to be improved by keeping this length of time. This is a question, however, which is still undetermined, and it deserves a further investigation. Under present conditions it is well to know the truth respecting these matters and to realize that the fresh meat we get, such as beef and mutton, is not direct from the shambles but has been kept for at least four weeks in cold storage.
Effect of Long Cold Storage.
—It has been stated in semi-scientific publications that the flesh of a mammoth incrusted in polar ice and presumably thousands of years old has been found to be intact and edible. This story, lacking corroboration, is hardly in harmony with known facts. The author had the opportunity of examining a quarter of beef which had been kept frozen in a warehouse for more than eleven years. This meat was found to be wholly inedible. It had an unpleasant and mummy-like odor, was light in fiber and color, having evidently lost a large part of its weight, and was of a character wholly unsuitable for consumption. This fact appears to show that eleven years is too long a time in which to keep meat frozen. In fact, it is scarcely worth while, from a practical point of view, to discuss so long a limit. Only the necessary time for the preparation and transportation of the meat is to be considered, and the sanitary laws of the nation, states, and municipalities should undoubtedly regulate the time of cold storage and see that all packages of meat exposed for sale are plainly tagged as to the date of slaughter, in order that the consumer may know.
In the consideration of the subject of preserved meats there are excluded all meats delivered in the fresh state for consumption and meats kept in cold storage in a fresh state during the necessary time of preparation and transportation say, on the whole, from four to eight weeks. Meats kept longer than this may generally be considered as preserved meats, even when cold is the only factor active in their preservation.
Method of Preserving Meats.
—Aside from cold storage there are four methods in vogue for preserving meats. These may be classified as follows: (1) Curing with the aid of condimental substances; (2) treatment with chemical and non-condimental preservatives; (3) sterilization with heat; (4) drying. These all except the second may be regarded as legitimate means of preserving meats.
Curing with Condimental Substances.
—This method of preserving meat has been practiced from the remotest antiquity. The chief condimental substances employed are salt, sugar, vinegar, and wood smoke. With the proper technical skill and knowledge of the process, meats can be preserved in this way, and at the same time aromas and flavors developed which are considered most agreeable by the consumer and which give an additional value to the product. It is not to be claimed in any case that condimental preservatives add anything to the nutritive value of the product, except in so far as condiments themselves aid the digestion by exciting in a perfectly proper way the activity of the glands which secrete the digestive ferments.
It is not the purpose here to describe the technical processes used. In general it may be said that the application of salt is the first process, and this is done as soon after the slaughter as possible to secure the proper cooling of the carcass, usually from twenty-four to forty-eight hours. The meat, properly cut into the forms known to commerce, is carefully packed and heavily salted, and allowed to remain for some time in contact with the salt or with the brine which is produced therefrom. The salt penetrates to the interior of the flesh and hardens, to some extent, the tissues, abstracting water therefrom, and, without being wholly germicidal in character, prevents the introduction of eggs of insects and the development of ordinary germ life. The salt, however, does not entirely inhibit the enzymic action which tends to ripen the meat and make it more palatable. It naturally gives to the meat the salty flavor which is demanded by the taste in a preparation of this kind.
Sugar is used, if at all, always in connection with salt as a preservative for meats. It may be employed in the pure state, but is usually the yellow or low-grade sugar or molasses. It gives to the preserved meat, especially ham, a flavor and quality much appreciated by the consumer.
The application of wood smoke is usually the last process after the meats are properly cured in salt and sugar. The pieces are suspended in a convenient room and underneath is built a fire of hard wood, which is kept smouldering as much as possible in order to produce the maximum of smoke and minimum of heat. Oak, maple, and hickory woods are most highly prized for this purpose, since they develop on burning a rich aroma which imparts to the flesh a delicate flavor.
The object of curing the meat is, first, to prevent decay; second, to impart the flavor of the well known condiments mentioned above, and third, to favor the development of the enzymic action which has the property not only to make the meat more aromatic than it otherwise would be, but also more pleasant to the taste.
The curing of meat in this respect may be compared to the development of a cheese, except that the enzymic action in the case of meat is one of minimum extent, while in the case of cheese it is one of maximum intensity. In addition to the condimental substances above mentioned spices of different kinds are sometimes added. Vinegar is also used at times as a condimental substance and is, to a certain extent, also a preservative substance, but vinegar is chiefly used in the preservation of vegetable substances rather than meats in bulk. For meats which are spiced as well as preserved as above, vinegar is often used as one of the ingredients, intended as a condimental substance. No other substances than those mentioned above are necessary to the proper curing of meat, but convenience of application and certain other considerations have led packers of meats, when not prevented by law, to abandon the old methods to a certain extent and substitute what is known as the quick-aging process described below.
Preservation by Means of Non-condimental Chemical Preservatives.
—The use of non-condimental chemicals in the preservation of meat is practically an industry of the last quarter of a century. Up to that time the use of non-condimental chemicals was practically unknown in the meat industry. The chemicals employed are those known as germicides. In the quantities used they neither impart a taste nor odor to a preserved meat, but by their germicidal properties prevent the development of organic ferments and thus make the preservation of meat far more certain and very much less expensive. By the use of some chemicals the salting, sugaring, and smoking of preserved meats may be done with very much less care, in a very much shorter time, and at a very greatly reduced expense. For this reason the practice has gained a great vogue, not as a means of benefiting the consumers, but rather as a means of enriching the packer and dealer. Chemical preservatives are also highly objectionable because they keep meats apparently fresh, while in reality changes of the most dangerous character may be going on. They thus prevent the display of the red light danger signal.
Preservatives Used.
—The principal chemical preservatives used in the curing of meats are borax and boric acid and sulfite of soda. There are many other chemical preservatives which have been employed, but these are by far the most useful, the most certain, and the most widely employed. Borax and boric acid, of the two classes, are by far the more common. Sulfite of soda is used more as a preservative of color, and is probably found more frequently on fresh than on preserved meats. Borax has the property of paralyzing fermentative action and thus securing immunity from decay. Its use, however, tends to diminish the palatability of the meat because of its restraining influence upon the condimental method of preservation described above. The meats are more quickly preserved, require less condimental substances, and the borax probably inhibits, to a certain degree, the enzymic action of a favorable kind, described above.
The use of any kind of a chemical preserving agent on meat is most reprehensible, no matter what they may be. Unfortunately, experts differ respecting the influence of these chemical preservatives upon health. The users of chemical preservatives have employed experts of known fame and distinction to testify in favor of these products, while the consumer, perhaps, is not able to go to the expense of securing expert testimony, and, therefore, as respects numbers of witnesses, at least, chemical preservatives have an advantage. In a case of this kind the accused must be considered guilty until proven innocent. It is not sufficient to prove in a given case that borax is not injurious. If it be proven that it is injurious in a single case conviction must ensue. There is no doubt of the fact that the injurious character of borax, even in small quantities, has been fully established, and therefore any amount of testimony to the effect that in individual cases it has not produced injurious results is of no value whatever. If a citizen be robbed and in the course of the prosecution it be shown that there are a million citizens who have not been robbed by this criminal the evidence would be of no value. If it has been shown that the individual citizen has been robbed the prisoner is convicted. No expert would testify that borax has never been injurious,—even those who appear in its favor admit that, but plead that it is generally used in small quantities, and, therefore, cannot be harmful.
The Argument of Small Quantities.
—The fallacy of the argument for small quantities is so evident that it needs only to be presented in brief form to show the intelligent and thinking people of this country the fallacy of the claims of experts in favor of chemical preservatives.
The arguments which have been advanced in excuse of the use of preservatives when used in minute quantities have, perhaps, been more vigorously urged for salicylic acid than for almost any other substance. This argument has been urged with such vigor and such ingenuity that a further reference may not be out of place here. The principle which is laid down is that a substance which is injurious to health when added to foods, if not a natural constituent thereof, or if not added for condimental purposes, does not lose its power of injury to health because it is diluted or given in small quantities. The only change which is made is to mask the injurious effects produced—to make them more difficult of ascertainment and impossible of measurement. The fallacy of the argument that small quantities of an injurious substance are not injurious may, perhaps, be best represented graphically. The accompanying chart ([Fig. 7]) shows theoretically the normal and lethal dose of a food and a drug or, as in this case, a chemical preservative. The chart shows two curves, one representing a chemical preservative and one representing a food. The normal dose of a food is that quantity of food which maintains a healthy adult body in equilibrium. It is represented in the chart on the right by the number 100. If the quantity of food necessary to maintain the equilibrium in a healthy adult body is slightly diminished, no apparent change is at first experienced and possibly even no discomfort. If, however, the quantity of food be still further diminished progressively, as indicated by following the curve down to the left, the point is finally reached when no food is given at all and death ensues, represented by 0 on the left hand of the diagram designated “Lethal dose.” As the curve begins to deviate from the perpendicular on the right the degree of injury is very readily noticed and starvation or symptoms of starvation are set up. Thus if you follow the perpendicular on the right downward to the point 80 the divergence of the corresponding point of the curve is already measurable. As you descend to 0 the magnitude of the measurement increases. It requires but very little further illustration to show how easily the effect of diminishing the normal dose of a food can be measured immediately after the curve begins to vary appreciably from the perpendicular on the right.
Fig. 7.—Graphic Chart Representing the Comparative Influences of Foods And Preservatives.
Let us now consider the perpendicular on the left, which is marked at the top under the term “Lethal dose,” namely, a quantity of the added preservative sufficient to destroy life. The normal dose of such an added chemical preservative is 0 and is shown at the base line to the right, marked “Normal dose.” If you add a very minute quantity of a chemical preservative, the curve representing it varies so slightly from the horizontal base as to be impossible of measurement by ordinary means. If we follow along to the number 75 on the horizontal base we see the deviation of the curve is sufficiently great to measure. At 50 it is still greater, at 25 still greater, while at the left of the basic line it is a maximum extending from 0 to 100, or the lethal dose. It is easy to show by mathematical data that no matter how small the quantity of an injurious substance or preservative it will still produce an injurious effect which may be infinitely small if the dose be infinitely small. It follows, then, as a mathematical demonstration that any quantity of an injurious substance added to a food product must of necessity be injurious, provided it is in the nature of a drug and the body is in a perfectly healthy, normal condition.
Hence the argument which has been so persistently urged in favor of a chemical preservative, that if in small quantities it is harmless, is shown to be wholly untenable. While there is no necessity for the addition of a harmful substance, where no particular benefit is secured thereby, and where there is no disturbance of the normal state of health, there can be no possible excuse of a valid nature to offer for the exhibition of even minute quantities. That these minute quantities would not be dangerous in so far as producing any fatal effect is concerned is conceded, but that in the end they do not produce an injury even in these small quantities is certainly to be denied. The course of safety, therefore, in all these cases is to guard the opening of the door. If the admission of small quantities is permitted, then there can never be any agreement among experts or others respecting the magnitude of the small quantity, and continued litigation and disagreement must follow. On the other hand, when the harmfulness of any substance which it is proposed to add to food is established and no reason for its use can be given other than the convenience, carelessness, or indifference of the manufacturer, the exclusion of such bodies entirely from food products follows as a logical sequence and a hygienic necessity.
The third method of preparing or preserving meat is by sterilization. Of all the various methods which have been proposed there is probably none which is, theoretically, so free of objections as the preservation of meat by sterilization, in other words, as canned meats. The only important thing is that the raw material used in canning must itself be meat free of disease, obtained under sanitary conditions, and subjected to sterilization before any fermentation or decay takes place. Pure, wholesome meat thus prepared and thoroughly sterilized will remain in an edible condition for a reasonable length of time. Unfortunately, as has been shown in the testimony respecting the packing industry of the country, canned meats have not always been selected solely for freedom from disease and for palatability. The question of diseased meat is discussed in another part of this book and, therefore, may not be taken up here. There have been used for canning purposes the fragments and, perhaps, inedible portions of carcasses, and this practice cannot be too severely condemned. This does not mean that these fragments and portions of carcasses are not fit for food, but they should be collected, prepared, and sold as such with plain notices to the consumers of their origin. A cheaper supply of beef would thus be furnished for those in humbler circumstances, and no imposition of any kind would be practiced because the nature of the meat would be fully understood.
Preparation of Meat for Canning.
—In the following description it is understood that the ordinary processes of canning sound, properly prepared beef are described. The question of the canning of improper samples is reserved for the remarks on adulterations.
There is no uniform practice followed, as has been carefully ascertained by a study of the different packing houses and processes for selecting and preparing meats for canning. The exigencies of trade determine this to a greater or less extent. When there is a demand in the fresh state for all the beef which can be supplied the canning industry will necessarily suffer. When there is a surplus of beef offered for sale or in case of war, where the army contracts for large quantities of canned meat, the opposite conditions probably prevail, and the best meats are used for canning purposes and those of a less desirable quality offered for sale in the fresh state. The portions of the carcass used, as described in Bulletin 13, Part 10, Bureau of Chemistry, depend, to some extent, upon the market of fresh beef. All of the meat on the fore quarter, except the shank and the “third rib,” is usually canned, and in some cases those portions are not reserved. The cheaper cuts from the hind quarter are also used for preserving purposes. Very fat, and therefore easily marketed, carcasses are not used for canning purposes except in case of unusual demand as above stated. There are two reasons for this, one of which has already been outlined, namely, that such meat brings a better price in the fresh state, and, in the second place, lean meat has a better appearance in the canned state than the fat meat. For these reasons, in the proper preparation of the meat for canning, the more fatty portions, together with the gristle, are removed and sent to other parts of the factory for making up into other kinds of food.
The meat having been selected, it is cut into pieces of approximately from one to four pounds in weight, according to the size of the tins in which it is to be placed. It is important, for the purpose of appearances, that the size of the pieces of meat in each tin be approximately the same. Also for the process of sterilization the pieces of meat should be practically the same size, so that they can all be thoroughly sterilized at the same time. If the pieces be of different sizes the small ones would become thoroughly cooked and disintegrated before the large ones became thoroughly sterilized, and thus the mass which would be presented to the view on opening the can would be unpleasant to the sight.
Parboiling.
—After the pieces have been selected and dressed they are parboiled before being sterilized. The time of parboiling varies in different packing establishments from eight to twenty minutes, according to the size of the pieces of meat. In some cases a uniform time for parboiling is prescribed, irrespective of the size of the pieces. One of the principal reasons for parboiling the meat is to secure the shrinkage, which always takes place on heating, before the meat is placed in the tins.
The experiments have shown that meats when put in tins in a fresh state and sterilized shrink to about two-thirds of their original volume. Parboiling is, in the essence, a process of shrinking. When the meat is put at once into boiling water there is less loss of protein matter than when the meat is placed in cold water and heated gradually. The substances removed in parboiling are water, fat, soluble mineral matter, and the meat bases. The fat is removed by becoming rendered, and rises to the surface where it can be skimmed off. A little over one percent of the protein content of meat is lost by parboiling while the total meat bases lost amount to almost one-third of the total quantity contained in the meat. Of mineral matter in the meat as high as 50 percent is lost in parboiling.
By shrinking, parboiling tends to make a more concentrated article and thus favors transportation. Practically the nutritive value of a pound of properly canned beef is about one-third greater than that of one pound of the fresh beef of the same kind. Hence parboiling may be regarded as a perfectly legitimate and desirable process without which the beef could not be properly prepared for canning.
Tinning.
—After the meat is properly parboiled it is placed in the tins either by machinery or by hand. To each tin is added a small quantity of a liquid preparation made by the canners and known as soup liquor. This liquor generally contains salt, and sometimes a little sugar or molasses. The composition of soup liquor is as follows:
| Solids, | .92 | percent |
| Protein, | .09 | „ |
| Meat bases, | .23 | „ |
| Ash, | .28 | „ |
| Salt, | .11 | „ |
| Water, | 98.37 | „ |
This soup liquor may be regarded as a thin soup. The origin of the liquid analyzed above was not disclosed, and, therefore, no expression can be made of the way in which it was formed. It was probably made from soup stock, namely, the waste meat and bones of the factory. There is no objection to a soup liquor of this kind provided it is made from sound, clean, and wholesome material. There are two reasons for adding this liquid, namely, to fill up the space which would otherwise exist between the pieces of meat and thus aid in the preservation of the material, and, second, to add a condimental substance which makes the contents of the tin more palatable.
Sterilization.
—After the cans are filled in this way and closed by soldering or otherwise they are placed in retorts which are composed of strong iron or steel boilers, properly covered and secured, and when these boilers are full they are subjected to the action of steam heat under pressure. Usually a small hole is left in the can through which any gas, air or other kind, is expelled from the can. As soon as everything is complete the retorts are opened and the cans are sealed.
In all cases, however, after sealing the cans they are subjected to a second heating at a temperature of from 225 to 250 degrees F. The time of heating varies from one to two hours. After removal from the retorts the cans are washed with a spray of cold water for several hours, and they are then dried, painted, and labeled.
The above is a general description of the process employed which, however, is varied to some extent in different packing houses.
A modification of the above method consists in exhausting the cans in vacuo and automatically sealing them in the exhausted state, thus removing all air and other gases therefrom. The cans are then placed upon an endless conveyor and dipped into an oil bath at a temperature of 240 degrees, the speed of the conveyer being so regulated that the cans remain in the bath a sufficient length of time to complete sterilization before being carried out at the opposite end. After passing through this bath they are carried automatically into another bath consisting of a solution of carbonate of soda and, finally, into a bath of pure water. The cans are then painted and labeled as originally described.