PRUNE (Lat. prunum, plum. prunes, plum tree, from Gk. rpormov, prounon, rporm.vov, proum non, plum, rporws, pronnos, rpo6,avn, proumne, plum tree). Any variety of plum which can be' successfully cured without removing the pit. Only those varieties which have a large propor time of solids, and sugar in particular, are con sidered good prunes. The prune industry was started in the Eastern United States in 1854, but failed because the climatic conditions were not favorable for the production of the desired quali ties. About 1863 the industry started in Cali fornia and grew rapidly. In 1880 the output had reached 200,000 pounds annually, and in )900, 100,000,000 pounds, thus developing in 30 years an industry with an annual output greater than France, hitherto the chief prune-producing nation of the world. Oregon, Washington, and Idaho also grow good prunes, as do also Servia, Germany, Spain, Australia, and South Africa.
The prune may be cured in three ways. (1) Sun-drying. the common and most economical way where climatic conditions will admit it. This is largely practiced in California, as well as in the European countries. The prunes are not picked until ready to fall. when they are gath ered, graded, and dipped in hot lye o• run through a pricking machine. after which they
are spread on boards or wire-bottomed frames and put out to dry, an operation which takes from S to 12 days, depending upon the variety, the size of the plum, and the weather. (2) They are treated by, evaporation, the drying being ef fected by fire heat. In this operation great care and skill are necessary, as too hot a fire will cause the fruits to burst, drip, and finally shrivel. If properly handled the evaporated product is superior to the sun-dried fruits. (3) The fruits in some European countries are partially cooked before being dried. Such prunes are softer than the sun-dried or evaporated ones. After being dried the fruit goes through a curing process, by being thrown into bins or heaps to sweat, which takes from one to three weeks. After this they are ready for 'processing,' which consists in dip ping fruits in boiling water and glycerin, steam ing, or by 'rattling' in a revolving cylinder. The object of this operation is to improve the color and appearance of the' fruit and to destroy the eggs of any insect which may be upon them. They are then ready for packing, the best prod ucts being placed in boxes, although many are packed in bags.