Report of the Ad Hoc Working Group on Methods of Analysis and Sampling[11]
47. The Chairman of the Working Group, Dr. R. Ellis (USA), presented the report of the Group.
48. The Committee agreed to give full recommendation to the method for sulfadimidine in cattle milk and provisional status to methods for azaperone/azaperol in pig tissues (3 methods); for chlortetracycline/oxytetracycline/tetracycline in muscle and kidney of cattle, pig and poultry and in cattle milk; for diclazuril in muscle, liver, kidney and fat of rabbit, sheep and poultry; for gentamicin in muscle, liver and kidney of cattle and pig; for isometamidium in muscle, liver, kidney and fat of cattle; for levamisole in pig liver, in liver of cattle, pig and sheep and in cattle milk; for neomycin in liver and kidney of cattle and pig; and for spiramycin/neospiramycin in muscle, liver, kidney and fat of cattle and poultry.[12] The Committee also agreed to delete provisionally recommended methods for albendazole in muscle, fat and milk: carbadox in muscle; chloramphenicol (4 methods) in muscle, milk and eggs; and trenbolone in muscle and liver because of the lack of multi-laboratory validation studies.
49. The Committee supported the proposal that greater emphasis should be given to the availability of analytical methods for compounds to be considered for JECFA evaluation.
50. The Group expressed its serious concern about the proposal of the Codex Committee on Methods of Analysis and Sampling that reference methods for Codex standards required validation by a minimum of six laboratories. The Committee noted that it had been difficult for analytical methods for veterinary drug residues to be validated by a minimum of three laboratories.[13]
51. The Committee thanked the Working Group and its Chairman and agreed to set up the ad hoc Working Group under Dr. R. Ellis (USA) at its next session.
Establishing Routine Methods to Meet Codex MRL Requirements[14]
52. The Delegation of Australia introduced the paper[15] and proposed that a country nominating a substance for inclusion in the priority list should commit itself to identify or develop a suitable validated method(s) of analysis to support MRLs. Many delegations expressed concern about the lack of validated methods to support Codex MRLs and of harmonized methods for regulatory purposes. In the case of older drugs, there had been special problems as sometimes sponsors were not identified or some methods available might use unacceptable reagents.
53. The Committee’s discussion mainly covered matters related to the availability and validation of methods, and whether an MRL needed to be set before a method could be recommended. The Committee noted that methods of analysis included in the submission to JECFA might be suitable for regulatory purposes but were not in the public domain. Furthermore, such methods would require inter-laboratory validation and to be available to regulatory authorities to be recommended for Codex purposes.
54. The Committee agreed that MRLs should be developed independently of validated methods, but such methods should be available before the Committee advances MRLs to Step 8. The Committee requested the Delegation of Australia, in collaboration with Canada, France, Germany, the Netherlands, United Kingdom, United States, COMISA and IDF to prepare a paper for consideration at the next session to help the Committee decide how best to proceed in the light of the points raised. The paper should include the criteria for a validated analytical method, how such a method should be developed in relation to the Codex Step Procedure, and the responsibilities of countries, manufacturers and other bodies involved. Input from the JECFA Secretariat should be sought. The FAO Joint Secretary of JECFA undertook to identify appropriate methods of analysis in previous submissions to JECFA.
