Advances in the safety evaluation of food additives. A conceptual and historical overview of the Acceptable Daily Intake (ADI) and Acceptable Daily Intake 'not specified'.

The Acceptable Daily Intake (ADI) is an internationally recognized quantified expression of the acceptability of food additives. It embraces both a concept and a numerical expression. This paper describes the conceptual origin and progression of this instrument of risk assessment and management in the framework of its history which encompasses three sequential stages: developmental, consolidation and contemporary periods. The review narrates in retrospect how the ADI originated, how it developed, and delineates in prospective its future evolution in the light of advances in the safety evaluation of food additives.