Estimate of the amount of a potentially harmful substance (e.g. contaminant) in food or drinking water that can be ingested daily over a lifetime without appreciable health risk.

Note 1: For regulation of substances that cannot be easily avoided, a provisionally tolerable weekly intake (PTWI) may be applied as a temporary limit.

Note 2: Acceptable Daily Intake is normally used for substances not known to be harmful, such as food additives.