On August 17, the U.S. Food and Drug Administration (FDA) published a long awaited final rule to clarify the regulatory criteria for determining that a food ingredient or substance is Generally Recognized As Safe (GRAS).  As established by the rule, a new voluntary GRAS notification procedure will replace the current voluntary GRAS petition procedure.
FDA has premarket review authority for food additives, but substances can be added to a food  without a pre-market approval if the manufacturer affirms the substance is generally recognized as safe by qualified experts for its intended use in human or animal food. Under the final rule, a substance cannot be classified as GRAS unless the available data and information satisfy the safety standard for food additives under the FD&C Act. 
The new rule clarifies the criteria and types of scientific evidence acceptable for the determining the safety of a substance.   Under the rule, the safety of a substance must be established by “generally available and accepted scientific data, information or methods, which ordinarily are published as well as the application of scientific principles”.  Unpublished data, information or methods can be used to corroborate scientific principles.
A GRAS notification must be prepared and submitted in a narrative format.  The written notification must describe how the available data, scientific information and methods supported the conclusion of GRAS.   References must be supplied for all data and other information described within a GRAS notice.
Following the evaluation of a GRAS notification, FDA would respond within 180 days with one of three categories of response letter: (1) “No questions letter”; (2) “insufficient basis letter”; and (3) “cease to evaluate letter.” The category, “cease to evaluate” refers to situations in which a company asks the agency to stop the evaluation.

Sources: U.S. Food and Drug Administration