BUTTER.—The Aylesbury Dairy Co. are the proprietors of a preservative for butter, the composi tion of which is kept secret. Butter preserved with the compound has remained good for more than a year, under most trying conditions. The process should be the means of introducing large quantities of fresh butter from distant pastoral countries.
alluding to recent processes for preserving fish in a fresh state, some space may be devoted to the ordinary methods of curing fish.
Herrings.—The fish are spread on a floor, and sprinkled with salt ; when sufficiently salted, they are thrown into large vats, and washed. Each fish is then threaded through the gills, on long thin spits, holding 25 each. These are hung upon trestles in the smoking-room, where fires of oak boughs are kept smouldering. For "bloaters," to be consumed in England, the smoking lasts about 24 hours ; "red-herrings" for export are salted more, and are smoked for 3 or 4 to 40 days, usually about 14 days. "Kippers" are taken while fresh, and split up. They are then washed, and thrown into vats with plenty of salt for a few minutes ; finally they are spread out on tenter. hooks on racks, and hung up for 8 hours' smoking.
Oysters.—A method of preserving oysters is adopted by the Chinese. The fish are taken from the shells, plunged into boiling water for an instant, and then exposed to the sun till all the moisture is removed. They remain fresh for a long time, and retain their full flavour. Only the fattest can be so treated. Oysters are also largely " canned," much in the same way as salmon.
Salmon.—The fish are beheaded and cleaned, and cut by a series of knives into the right lengths to fill 1-lb. cans. When these have been filled to within in. of the top, the covers are put on and soldered. In an air-tight condition, the full cans are passed to the boilers, vats measuring 5 ft. x 4 ft. x 4 ft., where they are steamed for 1 hour. They are then taken out and cooled. A small hole in the centre of each lid, hitherto remaining soldered up, is opened by applying a hot iron, and the air and cooking-gases are allowed to escape. The cans are then instantaneously made air-tight again, and are boiled for two hours in a bath of salted water, the salt being added to raise the boiling-point. They are then left to stand till quite cool.
Sardin•s.—The beheaded and cleaned fish are spread upon sieves, and plunged for 1-2 minutes beneath the surface of boiling oil in coppers. After draining a little, the fish are packed closely in tin boxes, which are filled up with pure cold oil, and soldered. The quality deteriorates with every immersion, owing to the matters disengaged by the boiling oil, and the coppers need frequent replenishing with oil.
Shrimps.—To preserve shrimps in a dried state, they are boile1 for 4 hour with frequent sprinkling of salt ; then spread out on hard dry ground, with frequent turning, to dry and bleach for 3-4 days. They are then trampled to remove the shells, and are winnowed and bagged.
Eckirt's process.—This consists in the application of an antiseptic under great pressure. The
antiseptic solution is made by adding 33 lb. of salt, sod I lb. saltpetre to 100 lb. of water; and -I lb. of salicylic acid to 100 lb. of water. A mixture is then made of 75 parts of the salt solution and 25 parts of the salicylic acid solution. This is applied under a pressure of at least 12 Eamon. The goods are then packed in barrels or cases, and surrounded with gelatine, to exclude the air, and prevent desiccation. The fish keep good and retain their flavour for 10-14 days. The same process is applicable to meat, game, &c.
Refrigeration.—This process, described further on under Meat, is equally applicable to all kinds of fish.
Fruit, Grain, and the preservation of grain, no further precautions are necessary beyond gathering it when ripe, and keeping it dry. The preservation of fruit and vegetables may best be studied under the three heads of desiccation, pickling, and cooking.
Dzstcowriolf.—The simplest form of desiccation is by ordinary sun- and wind-drying, as conducted in hay-making. The next step is by radiated sun-heat, as in coffee-drying (see Coffee); a further advance is made by the application of artificial heat, as in hop-drying and tea-drying (see Hops, Tea). The primary object in all these cases is the removal of the water mechanically present, and without whose presence, fungoid growths and decay cannot exist. As a curative agent simply, the application of heat is, however, unnecessary and injurious, causing a partial destruction of the flavour, and more or less fermentative change. Research has proved that, between the limits of 0° and 15° (32° and 60° F.), vegetable substances retain their flavour and all other qualities, while giving up their moisture, no fermentative action being engendered. This has led to the adoption of the Cold-blast system.—Tho fruit or vegetables are deprived of moisture by subjection to dried air nt a low temperature. The air is compressed in a chamber containing chloride of calcium, or any other compound pussessing strong dehydrating qualities. Chloride of calcium is in practice probably the best, as it so readily gives up the absorbed water on being heated. The compressed and dried air is then admitted into a chamber containing tho substances to be treated. The expansion lowers its temperature somewhat, which should be maintained between 32° and 60° F. The substances are distributed throughout this chamber on perforated trays, so as to be fully exposed to the current of eold dry air passing through. All the moisture is thus removed, without the least detriment to the flavour, colour, and other virtues of the substance acted upon. The process has a great advantage over hot-drying, both in the cost entailed and the result achieved. Fruit and vegetables thus prepared, and packed with ordinary care, remain good for an indefinite period, and resume their natural shape and dimensions when placed in water.