Ampicillin

A broad-spectrum semisynthetic penicillin used against many bacterial diseases of cattle, pigs, sheep and poultry. It is excreted rapidly, mostly unchanged in the urine, with relatively small amounts appearing in milk — a profile that shapes the withdrawal periods and milk discard times regulators require. Like all veterinary antibiotics, its use in food animals is bounded by maximum residue limits in meat, milk and eggs and by stewardship rules meant to slow antimicrobial resistance. Residue surveillance programmes test for penicillins routinely, since even trace levels can trigger allergic reactions in sensitive consumers and disrupt fermented products.