Organic foods are produced using methods of organic farming – with limited modern synthetic inputs such as synthetic pesticides and chemical fertilizers, though organic pesticides, such asBt toxin, are still used. Organic foods are also not processed using irradiation, industrial solvents, or chemical food additives. The organic farming movement arose in the 1940s in response to the industrialization of agriculture that became known in the 1960s as the Green Revolution. Organic food production is a heavily regulated industry, distinct from private gardening. Currently, the European Union, the United States, Canada, Japan and many other countries require producers to obtain special certification in order to market food as organic within their borders. In the context of these regulations, organic food is food produced in a way that complies with organic standards set by national governments and international organizations.

Evidence on substantial differences between organic food and conventional food is insufficient to make claims that organic food is safer or healthier than conventional food.With respect to taste, the evidence is also insufficient to make scientific claims that organic food tastes better.

Meaning and origin of the term

For the vast majority of its history, agriculture can be described as having been organic; only during the 20th century was a large supply of new chemicals introduced to the food supply.The organic farming movement arose in the 1940s in response to the industrialization of agriculture known as the Green Revolution.

In 1939, Lord Northbourne coined the term organic farming in his book Look to the Land (1940), out of his conception of "the farm as organism," to describe a holistic, ecologically balanced approach to farming—in contrast to what he called chemical farming, which relied on "imported fertility" and "cannot be self-sufficient nor an organic whole." This is different from the scientific use of the term "organic," to refer to a class of molecules that contain carbon, especially those involved in the chemistry of life. This class of molecules includes everything likely to be considered edible, and include most pesticides and toxins too, therefore the term "organic" and, especially, the term "inorganic" (sometimes wrongly used as a contrast by the popular press) are both technically inaccurate and completely inappropriate when applied to farming, the production of food, and to foodstuffs themselves.

Early consumers interested in organic food would look for non-chemically treated, non-use of unapproved pesticides, fresh or minimally processed food. They mostly had to buy directly from growers: "Know your farmer, know your food" was the motto. Personal definitions of what constituted "organic" were developed through firsthand experience: by talking to farmers, seeing farm conditions, and farming activities. Small farms grew vegetables (and raised livestock) using organic farming practices, with or without certification, and the individual consumer monitored.

Small specialty health food stores and co-operatives were instrumental to bringing organic food to a wider audience. As demand for organic foods continued to increase, high volume sales through mass outlets such as supermarkets rapidly replaced the direct farmer connection. Today there is no limit to organic farm sizes and many large corporate farms currently have an organic division. However, for supermarket consumers, food production is not easily observable, and product labeling, like "certified organic", is relied on. Government regulations and third-party inspectors are looked to for assurance.