GRAS exemptions are granted for substances that are generally recognized, among experts qualified by scientific training and experience to evaluate their safety, as having been adequately shown through scientific procedures (or, in the case of a substance used in food prior to January 1, 1958, through either scientific procedures or through experience based on common use in food) to be safe under the conditions of their intended use.
The substance must be shown to be "generally recognized" as safe under the conditions of its intended use. The proponent of the exemption has the burden of proving that the use of the substance is "generally recognized" as safe. To establish such recognition, the proponent must show that there is a consensus of expert opinion regarding the safety of the use of the substance. However, the existence of a severe conflict among experts regarding the safety of a substance precludes a finding of general recognition.
When a use of a substance does not qualify for the GRAS exemption that use of the substance is subject to the premarket approval mandated by the FFDCA. In such circumstances, the FDA can take enforcement action to stop distribution of the food substance and foods containing it on the grounds that such foods are or contain an unlawful food additive.
A GRAS designation typically exists in one of three forms: