Cooking is the act of preparing food for consumption. The term is often used in the narrower sense of applying heat to chemically transform a food to change its flavor, texture, appearance, or nutritional properties.
Heating can sterilize the food (depending on temperature, cooking time, and technique used), in addition to softening the food by turning collagen into gelatin. 45 to 140°F (or the roughly equivalent range 5 to 60°C) is the "danger zone" in which bacteria thrive, and which must be avoided for safe handling of meat, poultry and dairy products. Refrigeration and freezing do not kill bacteria, but slow their growth.
Living foods diet adherents advise against the use of heat in the preparation of food: they believe that temperatures above 106°F (41°C) destroy essential enzymes in the food, which they believe are necessary for proper digestion and nutrition.
After humans mastered the fire thousands of years ago, cooking became a nearly universal cultural feature. Specific techniques and ingredients are often regional.
