Tetracyclines are broad spectrum antibiotics which have been used in many food-producing animal species for the treatment of infections, including respiratory, enteric, and soft tissue infections. They have also been known to be used prophylactically in the prevention of infections, and were historically used at sub-therapeutic doses as growth promoters. However, this practice has been banned in many areas worldwide, including the USA and European Union (EU) (European Commission, Press Release IP/05/1687, 22 December 2005) due to the increasing emergence of antibiotic resistance as well as potential associations with allergic reactions in both humans and animals.
The four most common Tetracyclines used in veterinary medicine today are Tetracycline itself, Chlortetracycline, Oxytetracycline, and Doxycycline. A Maximum Residue Limit (MRL) of 100ng/ml (ppb) has been set for Chlortetracycline, Oxytetracycline and Tetracycline in the muscle tissue of all food-producing species in the EU (Commission Regulation (EU) 37/2010). This covers food which is both produced in and imported into the EU.