The amount of an additive a person can consume daily over a lifetime without appreciable health risk — set with large safety margins.
How it works, step by step
Find the highest dose with no observed adverse effect in studies (NOAEL).
Divide by a safety factor — usually 100.
Express it per kg of body weight per day.
Typical intakes are usually far below the ADI.
Not a cliff
Going over the ADI occasionally doesn't mean harm; it's a lifetime benchmark.
Evidence & sources
An ADI is usually set at least 100 times lower than the highest dose that caused no effect in animal studies. Evidence: established. Known: Standard method of international food safety assessment. Unknown: Exceeding an ADI occasionally does not mean harm. Source: World Health Organization / FAO (JECFA), Principles and Methods for the Risk Assessment of Chemicals in Food (EHC 240) (2009).