frozen foods, products of the food preservation process of freezing. This process has been employed by people in the Arctic from prehistoric times. Eskimos throw fresh-caught fish on the ice to freeze, and naturally frozen fish have been a trade staple of the Great Lakes region of North America since the mid-19th cent. Brine and cold-room convection methods were in use in Europe and the United States from about 1860 for freezing meat, fish, poultry, and eggs. In the early part of the 20th cent. small fruits were frozen for manufacturers of preserves, bakery products, and ice cream. Freezing prevents food spoilage by inhibiting microorganic and enzyme action. Deterioration is rapid after thawing, since reactivated organisms attack cells injured by ice crystals. Earlier methods involved inserting the food into chilled brine or an ice and salt mixture. In flash freezing, commercially begun in Germany in the early 20th cent., rapid chilling gives less time for the diffusion of salts and water for microorganic action. Methods of quick freezing include direct contact with refrigeration, indirect cooling by contact of the product with refrigerated shelves, cold blasts, or a combination of these methods. The frozen food industry has expanded rapidly because of the labor-saving and space-saving advantages of frozen foods and because the freezing process generally involves less loss of taste, flavor, and appearance than do other methods; it has been paralleled by the development of suitable containers and of specialized methods of transportation, storage, and retailing.