Chapter 23 - Veterinary Drug Residues in Meat-Related Edible Tissues

Abstract

Veterinary drugs are chemicals used to control diseases in animals. If good veterinary practices are followed, these drugs are very useful and make it possible to obtain excellent and abundant food production. In order to protect the consumer’s health, foodstuffs of animal origin must not contain drug residues that might constitute a health hazard. A series of food-related issues together with food-related fear (additives, residues, the genetically modified products, animal cloning) have drawn consumers’ and authorities’ attention to food safety. New principles such as risk analysis, traceability, and an integrated food chain from farm to table have been introduced, with hormone and veterinary drug residues in food, in particular meat, being a highly topical case. The safety of residues is evaluated by setting a no observed (adverse) effect level (NOAEL) and using uncertainty factors to determine an acceptable daily intake (ADI) on which subsequently maximum residue limits (MRLs) are established. Veterinary drugs must be registered in government agency, which are also in charge of setting drug MRLs in food. In order to know trends in use of veterinary drugs, official drug residue monitoring programs are carried out by several countries. Different factors related to the drug (type of formulation, site and route of administration, dose, use of combinations, and time after administration) or animal (breed, animal age, sex, and body condition) can have profound effects on the pharmacokinetics and drug residue levels in meat and edible tissues. After animal drug administration, tissues with the highest drug residues are usually liver, kidney, and fat, with residues in meat being very low. However, as a consequence of several misuses (extralabel use, noncompliance with withdrawal periods) much higher residue levels may appear in meat and edible tissues and produce adverse effects on people consuming these foodstuffs and/or have an economic impact.