Health implications of residues of veterinary drugs and chemicals in animal tissues.

The animal drug approval process in the United States is based upon the premise that the presence of drug residues in meat and poultry above tolerance is a public health hazard. Tolerances represent the maximum level of concentration of antimicrobials permitted in animal tissues at the time of slaughter. The tolerances are intended to ensure that residual drugs will have no harmful effects if ingested. The purpose of this article is to present existing evidence of the acute and chronic health consequences that may occur because of food of animal origin contaminated with illegal residues above the tolerance. The impact of food-borne drug residues on the gut microflora, residue detection limitations, and the responsibility of the veterinary practitioner in ensuring food safety is discussed.