Cooking uses heat
Cooking, cookery, or culinary arts is the art, science and craft of using heat to make food more palatable, digestible, nutritious, or safe. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric stoves, to baking in various types of ovens, reflecting local conditions.
Types of cooking also depend on the skill levels and training of the cooks. Cooking is done both by people in their own dwellings and by professional cooks and chefs in restaurants and other food establishments.
Preparing food with heat or fire is an activity unique to humans. Archeological evidence of cooking fires from at least 300,000 years ago exists, but some estimate that humans started cooking up to 2 million years ago.The expansion of agriculture, commerce, trade, and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as the invention of pottery for holding and boiling of water, expanded cooking techniques. Some modern cooks apply advanced scientific techniques to food preparation to further enhance the flavor of the dish served.Food safety
Cooking can prevent many foodborne illnesses that would otherwise occur if the food is eaten raw. When heat is used in the preparation of food, it can kill or inactivate harmful organisms, such as bacteria and viruses, as well as various parasites such as tapeworms and Toxoplasma gondii. Food poisoning and other illness from uncooked or poorly prepared food may be caused by bacteria such as pathogenic strains of Escherichia coli, Salmonella typhimurium and Campylobacter, viruses such as noroviruses, and protozoa such as Entamoeba histolytica. Bacteria, viruses and parasites may be introduced through salad, meat that is uncooked or done rare, and unboiled water.The sterilizing effect of cooking depends on temperature, cooking time, and technique used. Some food spoilage bacteria such as Clostridium botulinum or Bacillus cereus can form spores that survive boiling, which then germinate and regrow after the food has cooled. This makes it unsafe to reheat cooked food more than once.Cooking increases the digestibility of many foods which are inedible or poisonous when raw. For example, raw cereal grains are hard to digest, while kidney beans are toxic when raw or improperly cooked due to the presence of phytohaemagglutinin, which is inactivated by cooking for at least ten minutes at 100 °C (212 °F).Food safety depends on the safe preparation, handling, and storage of food. Food spoilage bacteria proliferate in the "Danger zone" temperature range from 40 to 140 °F (4 to 60 °C), food therefore should not be stored in this temperature range. Washing of hands and surfaces, especially when handling different meats, and keeping raw food separate from cooked food to avoid cross-contamination, are good practices in food preparation. Foods prepared on plastic cutting boards may be less likely to harbor bacteria than wooden ones. Washing and disinfecting cutting boards, especially after use with raw meat, poultry, or seafood, reduces the risk of contamination.