Veterinary Drug Residues

Veterinary drugs are used in livestock agriculture to treat disease, maintain herd and flock health, promote growth, improve meat quality in a sense of reducing fat and growing more muscles, and otherwise reduce production costs. With the agricultural use of drugs there is the potential of leaving residues that may appear in the food. Veterinary drug residues are the very small amounts of veterinary medicines that can remain in animal products and therefore make their way into the food chain. This includes any degradation products, which are the result of the medicine breaking down into its component parts. The chemical group of veterinary drugs is very diverse as is their application. Generally speaking there are two big groups of veterinary drugs, the antibiotic and the hormones.

Antibiotics
An antibiotic (from the Ancient Greek:ἀντί– anti, "against", and βίος– bios, "life") is a substance or compound that kills bacteria or inhibits their growth. Antibiotics belong to the broader group of antimicrobial compounds, used to treat infections caused by microorganisms, including fungi and protozoa. Antibiotics classified based on their mechanism of action, chemical structure, or spectrum of activity. Most antibiotics target bacterial functions or growth processes. Antibiotics that target the bacterial cell wall (penicillins, cephalosporins), or cell membrane (polymixins), or interfere with essential bacterial enzymes (quinolones, sulfonamides) are usually bactericidal in nature. Those that target protein synthesis, such as the aminoglycosides, macrolides, and tetracyclines, are usually bacteriostatic. Most antibiotics that occur naturally are produced by fungi, though nowadays the industrial production of them is synthetically or semisythetically.

Hormones acting as growth promotors
A hormone (from Greek ὁρμή - "impetus") is a chemical messenger produced by all multicellular organisms. They are released by a cell in one part of the body and will affect cells in other parts of the organism. Hormones are used for breeding to enhance body protein accretion, metabolize fat stores and increase lean growth rate. Growth promotion with anabolic hormone treatment goes up to 20% compared to non treated animals.

19-Nortestosteron
Acetygestagens
(Medroxyprogesterone acetate)

Government regulatory authorities control the use of veterinary drugs by approving or registering safe uses and monitoring food for unsafe or prohibited residues. There are several regulations in place which veterinary drugs are allowed to be used for food production and which are banned. For example Commission Regulation (EU) No 37/2009 of December 2009 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin or FDA Title 21 – Food and Drugs – Chapter 1 – Food and Drug Administration Department of Health and Human Services – Subchapter E – Animal Drugs, Feed and related products see for example Part 520 (Oral dosage form new animal drugs)

Looking at regulations for veterinary drug residues in food it is important to mention that there are Maximum Residue Limits (MRLs) and Minimum Required Performance Limits (MRPLs).

MRLs are the maximum concentration of residues following administration of a veterinary medicine which is legally permitted or acceptable in food. MRL values are therefore determined as not to pose a risk for human health. MRLs define how much of a residue can be left in the food.
MRPLs define method performance requirements to come as close as possible to determine if “nothing” is left in food.

To analyze veterinary drug residues in food there are several options from rapid screening techniques as ELISA and lateral flow tests to confirmatory analysis like liquid chromatography or gas chromatography. Romer Labs® offers ELISA Testkits for fast and easy testing of food for drug residues (AgraQuant Drug Residue ELISA Testkits) and a range of reference materials, which are also available ¹³C labelled in dried down format.