In food safety, the concept of substantial equivalence holds that the safety of a new food, particularly one that has been genetically modified (GM), may be assessed by comparing it with a similar traditional food that has proven safe in normal use over time. It was first formulated as a food safety policy in 1993, by the Organisation for Economic Co-operation and Development (OECD). As part of a food safety testing process, substantial equivalence is the initial step, establishing toxicological and nutritional differences in the new food compared to a conventional counterpart—differences are analyzed and evaluated, and further testing may be conducted, leading to a final safety assessment. Substantial equivalence is the underlying principle in GM food safety assessment for a number of national and international agencies, including the Canadian Food Inspection Agency (CFIA), Japan's Ministry of Health, Labour and Welfare (MHLW), the US Food and Drug Administration (FDA), and the United Nations' Food and Agriculture Organization (FAO) and World Health Organization. Origin The concept of comparing genetically modified foods to traditional foods as a basis for safety assessment was first introduced as a recommendation during the 1990 Joint FAO/WHO Expert Consultation on biotechnology and food safety (a scientific conference of officials and industry), although the term substantial equivalence was not used. Adopting the term, substantial equivalence was formulated as a food safety policy by the OECD, first described in their 1993 report, "Safety Evaluation of Foods Derived by Modern Biotechnology: Concepts and Principles. The term was borrowed from the FDA's 1976 substantial equivalence definition for new medical devices—under Premarket Notification 510(k), a new Class II device that is essentially similar to an existing device can be cleared for release without further testing. The underlying approach of comparing a new product or technique to an existing one has long been used in various fields of science and technology. Description The OECD bases the substantial equivalence principle on a definition of food safety where we can assume that a food is safe for consumption if it has been eaten over time without evident harm. It recognizes that traditional foods may naturally contain toxic components (usually called antinutrients)—such as the glycoalkaloids solanine in potatoes and alpha-tomatine in tomatoes—which do not affect their safety when prepared and eaten in traditional ways. The report proposes that, while biotechnology broadens the scope of food modification, it does not inherently introduce additional risk, and therefore, GM