Food preservation can be defined as the keeping of perishable foods in a consumable form for a long period of time. This can be accomplished in a number of ways, each dependent upon the type of food being preserved. Refrigeration, freezing, pickling, salting, fermenting, drying, freeze-drying, smoking, salting, canning, and dehydrating are the most common methods used to prepare food for long-term storage.
As one can imagine, the preservation of food has been a major preoccupation of mankind for centuries. People have been preserving food since the beginning of recorded time and, surely, even before then to ensure that a supply of nourishment was available when fresh food was unobtainable as a result of climatic changes or natural disaster. In ancient times there were four fundamental methods of preserving: drying, salting, pickling, and fermenting. However, it has also been shown that in Paleolithic times, some food was kept in natural caves or cellars, underwater, or buried in holes dug deep in the earth, where the constant cold would serve to keep perishable food intact, a practice still held in many primitive societies today.