Antibiotic residues in animal-derived food.

Antibiotics are used extensively in food-producing animals to maintain optimal health and promote growth. The use of these drugs has the potential to leave drug-related residues such as parent drug and metabolites in meat, milk, and eggs. For those drugs that require a withholding period to ensure that residues in the food products are below established tolerances, methods of analysis are required. The majority of approved antibiotics are assayed by microbiological methods. Although these methods are suitable for screening for drug residues, they often lack the specificity and precision required of regulatory methods. Present requirements for regulatory methods have resulted in the submission of physical-chemical methods in support of New Animal Drug Applications for antibiotics.