THE ARGUMENT OF SMALL QUANTITIES.

39

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 o 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.

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 o and is shown at the base line to the right, marked

FIG. 7.-GRAPHIC CHART REPRESENTING THE COMPARATIVE INFLUENCES OF FOODS AND PRESERVATIVES.

"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 o 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 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. sition of soup liquor is as follows:

The compo

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.

SPECIAL STUDIES OF METHODS OF CANNING BEEF MADE IN BUREAU OF CHEMISTRY.

Composition of Beef Used for Canning.-Samples of fresh beef intended for canning purposes, and examined in the Bureau of Chemistry, have the following composition:

The sample, of which the above data are representative, was secured from a mass of meat weighing 356 pounds, after passing through a sausage grinder and being thoroughly mixed. The above data may therefore be regarded as the representative constituents of the usual grade, most carefully selected canning beef.

Effect of Parboiling.-A similar lot of meat secured in the same way and from the same carcass weighed 358 pounds and was parboiled as follows: The meat was placed in water in a steam-jacketed tank, the temperature of which stood at 196 degrees F. The reduction in the temperature caused by the meat was restored by heating the contents of the retort, and it was kept at 196 degrees F. for 15 minutes. It is thus seen that this parboiling was accomplished at a temperature below the boiling point of water. After the parboiling was completed it was found that the meat weighed 235 pounds, showing a net shrinkage in weight of 123 pounds. This sample of meat was