Page:The American Cyclopædia (1879) Volume XIII.djvu/847

 PRESERVATION OF FOOD return to the simpler and more stable com- pounds called inorganic. (See EREMACAUSIS, and FEKMENTATION.) The principal promoters of such decomposition are moisture, oxygen, and certain minute organisms. The art of preserving food in a manner to retain its flavor and natural qualities is chiefly modern, as the ancients only understood rude methods, the principal of which were drying and salting. Fruits may be preserved in six principal ways : 1. In the natural state. Most fruits, such as berries, peaches, and plums, can be kept in the natural state only a short time, except when frozen or near the freezing point. In a good refrigerator, kept cool by a circulation of cold dry air, these more perishable fruits may be kept in a natural state for many days. This is also the best method of preserving melons and oranges. Apples and pears may be kept in cool dry apartments put up in barrels. Well selected apples, enclosed in compact tissue paper and carefully packed in barrels, may be pre- served for nearly or quite a year. Pulverized charcoal dust is a very good material in which to pack the fruit. 2. Boiling and adding sirup, or the method of making what are commonly called " preserves." These are in three forms : whole or sliced fruit, jam, and jelly. When preserved whole or sliced, they may be boiled in a sirup made of two pounds of sugar to one of water, the quantity of sirup varying in par- ticular cases, but as a general rule being about once and a half the volume of fruit. They may also be heated alone with sugar, or packed in sugar without heating. Their keeping proper- ties are of course 7 increased by the coagulation of the albumen by heat and the destruction of ferments. Jams are made by reducing the fruit to a pulp (sometimes removing the skin and the seed, but often allowing them to re- main in the mass for flavoring), and conducting the subsequent processes on the same princi- ples as for whole fruit, excepting that jam is always cooked, and should as a rule contain rather more sugar. Jellies are made by boiling the fruit in a small portion of water, straining, and adding sugar, usually in quantities equal to the juice. All these preserves are better kept in glass jars, because they allow inspec- tion to detect incipient fermentation, which may be arrested by immediate reboiling and reduction of mass by evaporation. The jars may be covered with air-tight caps fitted with gum elastic, or, what is quite as good, with white paper glazed with white of egg. A tough leathery mould after a time usually forms upon the surface of the preserves, which is considered by good housekeepers as a pro- tection against fermentation. 3. Boiling and sealing in air-tight cans, with little or no sugar added, the principle of preservation being the destruction and exclusion of ferments, and also the exclusion of air. The jars are sealed with screw and gum elastic covers, or with solder, while they are filled with the fruit and steam. When the steam condenses, a vacuum remains. This method is carried on to a great extent in the principal fruit-growing districts, millions of cans being sent annually to the great mar- kets. 4. Fruits are dried in various ways. Berries are simply exposed, on hoards or coarse cotton cloth or gauze, to the heat of the sun, or in the shade to a current of warm dry ;iir. Apples, pears, and peaches may be cut into pieces and dried in the same way. When they reach the requisite degree of dry ness, indicated by a tough condition well known to the expe- rienced housekeeper or fruiterer, the juice has become sufficiently inspissated to resist the action of ferments ; and they may be protected from mould for many months by keeping them in a cool dry atmosphere. 5. Fruits may be frozen and their qualities retained for a long time in this condition, and in the absence of good refrigerating apparatus the crude process of freezing may be resorted to ; but keeping them in refrigerators at or a little above a temperature of 32 F., and considerably above the freezing point of the juices, is to be pre- ferred. South American and West Indian fruits, and those raised in the southern states and California, are now. commonly sent north in refrigerators. 6. By immersion in strong brine and subsequent preserving in vinegar, or by primary immersion in vinegar, alcohol, or brandy. The method with brine and vinegar is known as pickling, and is generally employed with those articles which are termed vegeta- bles instead of fruits, although peaches, plums, cherries, and berries are often preserved in vinegar. (See PICKLES.) Animal food may be preserved by several methods, of which the following are the chief : 1. By immersion in a solution of common salt, to which a- small por- tion of saltpetre is often added, called brine. This acts -by abstracting the juices from the meat, and also by preventing the development of organic germs and lessening the tendency to molecular change. 2. By packing the meat in salt, whereby the juices are abstracted ; then removing it and allowing it to dry, and pack- ing in boxes or barrels. 3. By rubbing with common salt, and drying in the sun, or in a current of dry air. 4. By salting and smo- king, by which means, in addition to the ab- straction of moisture by the salt, pyroligneous acid and creosote act upon the flesh, causing it to contract and harden, and also preventing the development of mould. 5. By drying in a current of warm air at about 140 F., or in the open air at even a lower temperature, when the air is comparatively free from ferment germs. The latter method has long been prac- tised, especially for " jerked beef," throughout Spanish America and in the warmer parts of the United States. This dried meat may be reduced to powder, packed in air-tight cans, and preserved for a long time. When mixed with fat, it forms the pemmican used in arctic voyages. Spices and dried berries are some- times added to it. (See PEMMICAN.) 6. By cooking, to coagulate the albumen, and then