Sakchai Sriboonsue, Thailand
1 Thailand's Food Safety Policy
Thailand declared 2004 to be the year of food safety. During the year special emphasis is placed on consumer protection which includes among others a particular reference to the awareness of drug residues in foods derived from animal products. The country has thus established guidelines of its Food Safety Policy outlined as follows.
A) The policy emphasizes an essential equivalence between domestic and international consumer in terms of food safety.
B) The policy declares that country's agricultural commodities shall be in general compliance with international standards.
C) The sanitary and phytosanitary standards shall be established on scientific basis.
D) The country shall implement standard control system as well as plant and animal quarantine that are in conformity to international level, covering from farm to table.
2 Control of drug residues in animal products
Thailand has established the prevention and control system that are complied with the government's policy as follows.
2.1 Regulation of manufacture, importing, registration and distribution of veterinary drugs.
Manufacture, importing, registration and distribution of human and animal drugs are regulated under Drug Act 1967 (B.E. 2510) and its five revised versions. A person who would like to manufacture import or sell the modern and/or traditional drug for animals shall need a permit issued by Thai Food and Drug Administration (Thai FDA), Ministry of Public Health. The registration of a drug formulation for veterinary drugs shall be acquired subject to the consideration of Animal Drug Committee comprising of representatives from related agencies. The criteria for such a consideration shall involve:
1) The drug's efficacy, quality and safety, for both animal and human health, has been demonstrated.
2) The drug is registered in the country of its manufacture and also has acquired there a certification for free sale.
3) The drug exists in a veterinary pharmacopoeia and has a reliable academic standing.
4) A new drug has gained enough academic recognition via publications in reputable scientific journals.
In addition to the legislation of veterinary drug acted by Food and Drug Administration, the Ministry of Public Health, the inspection of the related premises for drug distribution is a joint activity of the Ministry of Public Health and the Ministry of Agriculture and Cooperative. This allows an effective system to control the non-licensed products.
2.2 Regulation for the importation and distribution of chemicals
The importation and distribution of pharmaceutical raw materials is regulated by Food and Drugs Administration. Drug Act governs the distribution of the pharmaceutical raw materials to the licensed drugs manufactures and the pharmaceutical raw materials are not allowed to be used directly to the animals, such as in the farms.
For certain pharmaceutical raw materials those are restricted to non-food use, the Ministry of Commerce via the Import and Export Act 1979 (B.E. 2522) regulates the importation of those particular substances, for example, chloramphenicol, fluoroquinolone and nitrofurans.
2.3 Prudent use of veterinary drugs in farm
To promote the prudent use of veterinary drug in food animals, Thailand has adopted Codex Code of Practice for Control of the Use of Veterinary Drugs (CAC/RCP 38-1993) as a national standard. In accordance with the Code of Practice, veterinarians must supervise veterinary drugs being used in food animals.
2.4 Testing laboratory system
The country has established laboratories which are dedicated to inspect food commodities making certain that they are free of prohibited drugs and or the quantity of residues for drugs having MRL status is controlled. Moreover, raw material monitoring and surveillance are conducted in both pre and post production. These laboratories endeavour to develop methods of analysis that are internationally acceptable and recognized. The government has given initial support to establish 6 private central laboratories. Accreditation of private laboratories is also conducted in order to increase the analytical resources of the country.
2.5 Bases of controlling the drug residue in animal foods.
As already mentioned, Thailand controls the veterinary drug residues in food animals, has legislations that cover the selection of veterinary drugs, their imports, distributions and uses. Including provide such facilities to monitor drug residues. Thailand has adopted Codex Maximum Residues Limit (MRL) of Veterinary Drug as the basis of its food safety law. It is worth mentioning that MRL are established by Codex risk analysis procedure which provides an approval at the international level. In addition, the academic organizations have also undertaken risk assessments for the establishment of Maximum Residues Limit (MRL) of Veterinary Drug in foods.
3 Problems facing the establishment of ADI/MRL
The establishment of MRL for veterinary drug residues has an objective to protect consumers and to provide fair practices in food trade. Currently, however, there exist broad differences between Codex and member countries such as USA and EU in terms of MRL status of veterinary drugs. Also for a number of veterinary drugs MRL have not yet been allocated by Codex all; the latter drugs usually fall into the following two categories.
Among these drugs, there are some for which MRL status are established by member countries. Countries might have the same or different list of permitted drug based upon their own risk analysis. The usual trend is that a drug, for which a MRL cannot be established in each country, might be categorized as prohibited for use in food-producing animal and shall have no residue or zero tolerance. Due to the different limits of trace amounts in analysis (part per billion, part per trillion), the rejection pattern of animal products may still differ owing to discrepancies of detection methods used by different control laboratories. With this respect the following points should also be considered:1) Drugs that are proposed to Codex and evaluated by JECFA for which no ADI/MRL have been established (including those have a long history use) because of insufficient data and due to doubts on their impact on consumer safety due to their toxic properties.
2) Drugs that have not been proposed to Codex include those with either a long history of use or those that are new.
1) Due to the complexity and high cost of the procedure of assessment, some countries have not established MRL especially for drugs that are not used in the country or for those used in minor animal species. In Codex, there are a number of drugs that have no established MRL and there exists no reliable and approved analytical method to detect their residues. Under these circumstances the member countries usually assume a zero tolerance policy to these drugs while reliable and approved analytical methods to detect residues are not validated. This situation may lead to problems in international trade.
2) Codex definition of residues of veterinary drug includes the parent compound along with its metabolites and impurities. However, in some cases the metabolites may come from sources other than the parent drugs and they can be detected after no longer use of the drugs. An example in this case can be found in SEM that is used as unsuitable marker residue for nitrofurazone.
The gap that exists between regulations from many countries and Codex standards/guidelines has to be recognized for the purpose of consumer protection and fair trade. A comprehensive risk analysis including risk assessment, risk management, and risk communication for drug with no Codex or a single country's ADI/MRL should be generated to provide clarification. In addition, the zero-tolerance concept should be identified as an area where the elaboration of a guideline is needed as to when the concept can be used and how it relates to the analytical method used for the residue analysis.
4 Recommendations
Based on the risk-analysis data, each country might have a different profile of permitted drugs. Drugs with otherwise have a long history of successful use may face prohibition after introduction of regulations that set tougher registration criteria. The majority in this category of drugs lack a sponsor that can propose data to risk assessor and JECFA. In these cases the Codex encounters the problem of adopting MRLs.. In order to facilitate the work of Codex considering consumer safety in these cases, the following can be proposed.
1) For the drugs with a long history of use including those which have been evaluated by JECFA but for which an ADI/MRL could not be allocated due to insufficient data, but for which ADI/MRL were established by some Codex member countries, Codex should consider to adopt an operational Codex MRL or a temporary Codex MRL only to remain valid until further support by potential sponsors is available. Such drugs shall have the MRL established from the result of risk analysis available from member countries and be approved by JECFA/CCRVDF on that basis.
2) For those drugs for which member countries cannot establish MRL and/or for which no-residue is desirable, JECFA/CCRVDF should provide a normative reference of zero-tolerance term which should be related to a validated method of analysis to be used as approved reference/regulatory method. This may include performance-based criteria for sampling and analytical technique to be used when to detect drugs with no ADI/MRL.
3) It would be useful for risk management, risk communication if JECFA/CODEX can compile prohibited list of veterinary drugs.
4) International organizations and developed countries should have mechanisms to support member countries in aspects of knowledge sharing on the risk analysis of veterinary drugs and the analytical technology for the determination of veterinary drugs and drugs residue. Such a support will strengthen the system that encompasses the residue control. Further, establishing a network of reference laboratories specialized in veterinary-drug residue evaluation should be encouraged in each region.
