Veterinary drugsVeterinary drugs are among the substances that enter animals by intention. Some veterinary drugs such as worm cures (parasiticides) and drying-off formula are used preventively. Traces of the medicine can remain in the animal for a shorter or longer period before they leave the body in some form. To protect the health of the consumer, a determination has been made for every active ingredient in a veterinary drug, of how harmful that ingredient is and of the maximum residue limit (MRL), below which no negative effects are expected for consumer health. MRLs are set at the European level (Regulation 2377/90/EEC). Regulation 2377/90/EEC has four appendices:
- appendix I, substances for which definitive MRLs have been
- appendix II, substances for which it is not necessary to set a
- appendix III, substances for which provisional MRLs have been set and,
- appendix IV.
Appendix IV contains a list of substances, such as chloramphenicol and the nitrofuranes, that may not be used as a veterinary drug in animals kept for food production. No MRLs are set for these chemicals since they may not be present at all. The appendices to the regulation are regularly supplemented and amended. When a veterinary drug is registered, a waiting period is also set. This is the period following treatment, during which no products originating from the animal may be sold. The waiting period is intended to ensure that the meat no longer contains traces of the medicine exceeding the MRL when the animal is slaughtered.
The use of additives in animal feeds is restricted at the European level. Often additives may only be used in particular phases of the life of an animal. A ban on using additives in the period prior to slaughter is intended to ensure that no traces of additives are found in meat. Other substances that are sometimes deliberately administered to animals include the natural and synthetic hormones and ß-agonists. In the European union it is forbidden to add these chemicals.
The substances that may end up in meat unintentionally include environmental contaminants, such as organochlorine compounds, heavy metals and pesticides. Environmental contaminants and pesticides reach the animal via its feed and drinking water. The Commodity Act and the Pesticide Act lay down maximum levels of these chemicals in meat. This has implications for the composition of animal feeds.
Therefore the regulation on undesirable substances in animal feeds specifies the levels of a number of environmental contaminants and pesticides that may be found in animal feeds. This list of undesirable substances has recently been supplemented with a limit on dioxins in citrus pulp.