Veterinary residues
Fish and shellfish farmers sometimes need to use medicines to treat their fish. As a result, unwanted traces of the medicine may remain in the edible portion of the fish. Legislation is in place to specify maximum allowed levels of residues remaining in food. These are set sufficiently low to protect public health.
Background
Medicines may be used to treat food-producing animals if the medicines have been assessed and approved. Veterinary medicines tend to reside in the medicated animal for a period of time and therefore may be present in food derived from that animal. Residues of veterinary medicines are traces of medicine or its breakdown products remaining in the food. If necessary, maximum residue limits (MRLs) are established and in some cases the use of the drug is prohibited.
Internationally, the Codex Alimentarius Commission has set MRLs for a number of veterinary medicines in foods (Codex document CAC/MRL 02-2008). While these MRLs may have legal standing in some countries, they are not binding in the EU and are not harmonised with EU legislation. However, from 6 July 2009 onwards, Regulation 470/2009 provides a mechanism for the Commission to adopt certain MRLs set by Codex.
In the European context, the body that assesses veterinary medicines and advises the Commission on MRLs is the European Medicines Agency (EMEA). MRLs that are binding in the EU are set out in legislation.
In the UK, the Veterinary Medicines Directorate (VMD), a branch of Defra, manages the use of veterinary medicines and carries out surveillance of medical residues. With its statutory surveillance programme, the VMD monitors residues in locally produced food and reports the results. The VMD also runs a non-statutory residues programme with the main objective of looking for banned or unauthorised substances in imported food. The Veterinary Residues Committee (VRC) formulates the surveillance plans and interprets the findings. Port Health officials look for residues in imported food according to their veterinary checks regime, and they also help the VMD carry out its non-statutory programme.
Legislation
European legislation that deals with residues of veterinary medicines consists mainly of these pieces of legislation:
Directive 2001/82
Directive 2001/82, amended by Directive
2004/28, allows the use of
medicines in food-producing animals only if the medicines have been
assessed as safe according to Regulation 2377/90.
Regulations 470/2009, 37/2010 and 2377/90
Regulation 470/2009 replaced Regulation
2377/90 (the
MRL Regulation) on 6 July 2009. Like Regulation 2377/90, Regulation
490/2009 allows medicines to be administered to food animals only
if the substances are on a 'permitted' list, which is now in
Regulation 37/2010. Regulation 37/2010
lists allowed and prohibited substances:
- Table 1 is a list of allowed pharmacologically active substances for which MRLs have been fixed or for which MRLs are not necessary. A table of MRLs applicable to seafood is available here.
- Table 2 is a list of substances for which no maximum levels can be fixed because they are a hazard to human health at whatever level.
Regulation 470/2009 prohibits the administration of pharmacologically active substances that are not listed in Table 1. To avoid confusion with 'borderline' substances, the Commission has produced a list of substances 'considered as not falling within the scope' of the Regulation. The current list (6 Jan 12) is available here.
Regulation 470/2009 also introduces some new concepts:
Reference Points for Action (RPAs)
RPAs are maximum limits that may be applied to substances that are
not listed in Table 1 of Regulation 39/2010. Food will not be
allowed to be placed on the market if it contains a residue level
above the RPA. In contrast to the minimum required performance
limit (MRPL, mentioned below), which refers to the minimum
quantifiable amount of residue, the RPA is expected to define an
amount of residue that is more practically quantifiable using
approved analytical methods, while still applying the principles of
risk assessment. No RPAs have been set so far (November 2010).
Codex MRLs
In certain cases, the Commission will approve MRLs set by the Codex
Alimentarius and therefore bypass the full assessment normally
carried out by the EMEA.
Extrapolation
This allows the EMEA to apply MRLs established for a particular
foodstuff to other food stuffs, or to apply MRLs established for
one species to another species. The idea is to make veterinary
medicines more available, since medicines approved in a particular
context will not have to be subjected to a new trial specific to
the new foodstuff or species. Instead, there will be the
possibility of approval on the basis of available data. The EMEA
has produced a Position Paper (EMEA/CVMP/457/03) on
extrapolation of MRLs.
Directive 96/23/EC - the National Control Plan
Directive
Directive 96/23 requires
the monitoring of residues according to a national control plan.
Chapter VI of Directive 96/23/ECconstitutes the link between third
country food imports and veterinary residue legislation by
requiring that third countries provide guarantees that that their
control measures are equivalent to the ones outlined in the
Directive. Third countries have to provide guarantees that products
of animal origin outside the EU-style residue-monitoring system are
not presented for import.
Decision 2002/657 establishing MRPLs and Decision
2005/34 establishing a harmonised course of action if substances
with MRPLs are detected in third country imports
Decision 2002/657
describes the sensitivity required of analytical methods used to
monitor residues in foods. Importantly, it contains a list of
minimum required performance limits (MRPLs) for the analysis of the
prohibited substances listed in Table 2 of Regulation 37/2010. In
effect, the MRPLs define the lowest quantity of residue, usually an
Annex IV substance, that is quantifiable using the latest
technology. Food found to contain an Annex IV substance at or above
the MRPL can be said to contain the prohibited substance - the MRPL
is considered a reference point for action. Finding a residue level
below the MRPL may also require action if the finding indicates the
presence of the substance. MRPLs are currently as follows:
|
Substance and/or metabolite |
MRPL (µg/kg) |
|
Chloramphenicol |
0.3 |
|
Nitrofuran metabolites |
|
|
Sum of malachite green and leucomalachite green |
2 |
Guidance
EU guidance on residues of veterinary medicines is available on the DG Sanco website. DG Sanco lists the major developments to MRLs on its Public Health page here.
Further information is available from the EMEA's website, including a Question and Answer document on MRLs.
The UK's Veterinary Medicines Directorate (VMD) and Veterinary Residues Committee (VRC) web sites contain information on residue surveillance and legislation guidance.