Fig. 63b.—Left.—Top and bottom round. Right.—Round bone sirloin steak. Courtesy of Bureau of Publications, Teachers College.
For very complete and conveniently arranged tables giving the percentage composition, the food values per pound and per ounce, the weight and nutrients of the 100-Calorie portions of all the important meats and other food materials as well, see Rose’s “Laboratory Handbook for Dietetics.”
Dangers from meat.—Three dangers from meat must be recognized; (1) animal parasites, such as the trichina sometimes found in pork, (2) poisons developed in the meat by bacteria when it is kept too long or without sufficient refrigeration, this danger being recognized as ptomaine poisoning, (3) bacteria, sometimes present in meat, which are directly injurious to man and which are now held to be the cause of most of the sickness commonly attributed to ptomaine poisoning. Government protection must be given us here, but the housekeeper too has a responsibility. If the raw meat has failed to receive proper inspection, we can protect ourselves by cooking the meat to a degree that will kill any parasite present. For this reason meat should not be served that looks raw or too underdone. The cooked meat should be pink rather than red.
Meat poisoning may be avoided in the first place by exercising great care in regard to the odor of meat. Meat may hang to “ripen,” as the butchers say, but one must learn to distinguish between the odor of properly ripened meat, and that of even slightly tainted meat. Quite as important is the rapid cooling of meat, poultry, fish, and soups that are not to be used at once. Cases of digestive disturbance and even actual poisoning sometimes occur when underdone meat, especially lamb, veal, or poultry, remains warm overnight.
Fig. 64.—Composition of meats.
The effect of heat upon meat.—The fat of meat is melted by heat. The meat fiber shrinks and hardens
with intense heat; on the other hand it softens at a temperature somewhat below the boiling point of water. The structure of the muscle must be studied further in order to make the principles of cooking perfectly clear. If you think of the structure of the muscle cell as somewhat resembling the structure of an orange, you can picture quite clearly what happens under different conditions. Open a section of orange and separate some of the single cells. These may represent the muscle cells of meat that can be seen only under the microscope. If you cut across one of these tiny cells, the contents will escape, and this is what happens when the muscle cells are cut across. Then, too, if the muscle is heated, the juices will pass through the membrane of the cell, and this happens, too, if the meat is put into cold water. The substances in the juices of the meat which are not coagulated by heat are called the extractives, because they can be extracted by hot water. The most valuable protein matter remains behind in the muscle cell, however. Among these proteins are those known as meat albumin, and this behaves in cooking very much as does the white of egg,—that is to say, it coagulates.