For sterilizing food in cans and ot

For sterilizing food in cans and other containers, entirely different heaters are used.The containers must be heated to temperatures higher than the boiling point of water toachieve sterility in nonacid foods, and so large pressure cookers or retorts are used.Food may be heated or cooked using toasters, direct injection of steam, directcontact with flame, electronic energy as in microwave cookers, and so on; all of thesemethods are currently used in the food industry. Such processes as baking, frying, mostfood concentration, food dehydration, and various kinds of package closure all employthe unit operation of heating.