Читать книгу Foods and Their Adulteration - Harvey Washington Wiley - Страница 43

—The most satisfactory method of detecting meats is by means of their chemical examination. There are two distinct points which are kept in view in a chemical examination. One is the presence of glycogen, which in quantities of more than one percent is characteristic of horse meat. Unfortunately, this test can only be applied to a meat in practically a fresh state, as the glycogen is rapidly changed into other forms of carbohydrate substances which make it difficult to identify. The chemical examination, therefore, which is of the most value is that which is performed upon the fat. The fat of different animals has different physical and chemical characteristics. The fats crystallize in different forms and have different melting points,—also the fatty acids derived therefrom. They absorb different quantities of iodin and bromin, and have other physical and chemical properties which are peculiar to each variety.

A careful examination of the fat, therefore, will lead to an approximate degree of knowledge concerning the character of the flesh from which it has been derived. For instance, lard and beef fat are easily distinguished from each other. In case a minced meat is made wholly of one kind of flesh or of one kind of animal the chemical examination of the fat will, with a considerable degree of certainty, lead to its identification. In the same manner, if a minced meat be made up of equal parts of two different kinds of animals the characteristics of the fats will lead to the identification of the two sources of meat. If, however, one kind of meat be mixed in only a small proportion, say 10 or 15 percent, of another, the chemical methods of separation are not to be relied upon. None of these chemical or physical methods, unfortunately, is of value in the hands of any but an expert, and, therefore, cannot be regarded as a common means of identification. For this reason the only common manner of identification of the kinds of meats which are sent out to the consumer at large must consist in the general knowledge of their anatomical, physical, palatable, and gustatory properties outlined above.

In all cases the consumer must eventually rely upon the official inspection and the label which accompanies the meat or which should accompany it.