Thus, having discovered by trial and error which plants and animals were edible, primitive humans had to learn how to preserve such foods. In climates with cold winters or long arid spells, human survival might have depended on preserving food for many months. We will never know exactly how prehistoric people discovered them, but it seems certain that magic and practicality were inseparable. In the days before science, humans turned to religion for explanations. It also inhibits the growth of microorganisms, but some of these dormant germs can become dangerous when the food is rehydrated.
Heat can increase shelf life by temporarily sterilizing food.
But our ancient ancestors could not adequately cook many plant foods until they developed pottery and cooking vessels. Humans developed rudimentary cold storage by cooling the recesses of caves and other shelters with ice and snow. Fermentation is a gradual chemical change caused by the enzymes of some bacteria, molds and yeasts. Fermented beverages were common in the earliest civilizations of Mesopotamia and Egypt. Not only did wine facilitate conviviality, it was usually more potable than the available water.