Method of food preservation in which moisture (primarily water) is removed. Dehydration inhibits the growth of microorganisms and often reduces the bulk of food. It is an ancient practice, used by prehistoric peoples in sun-drying seeds, by North American Indians in sun-drying meat strips, and by the Japanese in drying fish and rice. It was used to prepare troop rations in World War II, and in recent decades campers and relief agencies have discovered its advantages. Commercial dehydration equipment includes tunnel dryers, kilns, and vacuum dryers. A combination of dehydration and freezing is used in the process of freeze-drying, whereby solid food remains frozen while its liquid escapes as vapour. The dairy industry is one of the largest producers of dehydrated foods, including whole milk, skim milk, and eggs.

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