Salicylic acid was formerly used as a milk preservative, but is now seldom used except in beers. All these preservatives are objectionable in milk, although their injurious action may be difficult to prove.
5. Coating with fat or gelatine has only succeeded in conjunction with the exclusion of air. This process is especially applicable to fishes, as tinned sardines. In a modified form, it is useful in coating potted meats, etc.
6. Heating and Air-tight Cases.—Tinned meats prepared according to this method are imported in large quantities. In the process of preparation, the cases are packed with meat and filled up with gravy, and then closed with a cover which is hermetically sealed, except at one point. The case is then heated to 250° Fahr., in order to drive out all air, and destroy any putrefactive germs present. The open point is sealed while the gravy is still boiling, thus making the case completely air-tight. Albumin is coagulated at about 170° Fahr.; the higher temperature, which it is found necessary to employ, overcooks the meat and renders it less digestible (see also p. 40).
[CHAPTER VII.]
CONDIMENTS AND BEVERAGES.
Condiments, etc.—The name condiment is used in various senses by different writers. In its strictest sense it is a substance containing a volatile oil or ether, which may be taken with salt, and the object of which is to excite the senses of taste and smell, and consequently produce an appetising effect. This definition excludes spices, substances allied to condiments, but usually taken with sugar, as cinnamon, ginger, etc.; also flavouring agents, such as vanilla; and acids, such as vinegar and lemon-juice. If we use the word in its widest sense, to include these various groups of substances, we find that all condiments are taken with the object of improving the taste or flavour of food, or of assisting its digestion; but that they are not foods in the sense of supplying any elements towards building up the body or maintaining its heat. The only partial exception is lemon-juice, the salts of which have a quasi-medicinal use.
Taste is usually a compound sensation, the organs of which are the nerves of taste and smell. True taste is confined to the appreciation of sensations of bitter and sweet; but the flavour of meats is nearly entirely appreciated by the sense of smell. This is shown by the fact that meats appear tasteless and insipid, during “a cold in the head.” In the appreciation of acid, astringent, and fiery substances, the sense of touch is also employed. The excitement of these different nerves results in a stimulus which is carried up to the central nervous system, and causes by reflex action an increased flow of the digestive juices. Hot substances, like cayenne and ginger, also cause an increased flow of gastric juice, by directly congesting the mucous membrane. This action is not so desirable as that through the influence of the nervous system. All natural foods are sapid and possessed of flavour, and thus stimulate secretion; but any local irritating effect ought to be avoided.
1. Condiments proper comprise chiefly mustard, pepper, cayenne, garlic, onion, capers, mint, sage, morels, mushrooms, truffles. The last three on the list are also foods, but are more commonly used as condiments.
All these act as stimulants to the digestive organs, and in small quantities aid digestion. The active principle of mustard and horse-radish is sulphocyanide of allyl. Horse-radish is not so wholesome as mustard, the scraped root being apt to adhere to the stomach like the skins of grapes, and produce indigestion. Pepper contains an acrid resin, a volatile oil, and an alkaloidal substance, called piperine. Cayenne contains an analogous substance, called capsicin. Cayenne, unless in extreme moderation, is harmful, as its small particles adhere to the mucous membrane of the stomach, and may set up considerable irritation.
2. Spices are those condiments which contain an aromatic oil, and which harmonize with sugar. They are, as a rule, less irritating to the stomach than those of the pepper group. Cinnamon, cloves, camphor, ginger, and curry powder are the chief of these. Curry powder really belongs to both the first and second divisions. When genuine, it is said to contain turmeric, cardamoms, ginger, allspice, cloves, black pepper, coriander, cayenne, and a few other substances.