|FAO manual on the submission and evaluation of pesticide residues data for the estimation of maximum residue levels in food and feed (1997)|
This Manual is limited to the procedure followed by the FAO Panel of Experts.
The evaluations carried out by the JMPR comprise three main categories:
· review of new compounds (compounds evaluated by the JMPR for the first time);
· review of compounds under the periodic review programme;
· re-evaluation of new information relating to compounds other than new or periodic review chemicals.
The principles of evaluation of new compounds and compounds under the periodic review programme are very similar and follow the order of subjects described under Data Requirements (Section 3.1). Re-evaluation of a compound is carried out when new information related to its use and residue levels becomes available (e.g. change in or new use patterns, data on metabolism, residue behaviour, etc.). The re-evaluation often deals with and clarifies a single question raised by the Codex Committee on Pesticide Residues. The scope and depth of periodic review and re-evaluations are substantially different, and they are explained in section 5.2.2. To make a clear distinction between the periodic review and re-evaluation of compounds, the latter is often referred to by the FAO Panel as normal re-evaluation.
The agenda of the meetings is decided by the Joint Secretaries of FAO and WHO, based on the priority list proposed by the Codex Committee on Pesticide Residues and approved by CAC, and on the information on availability of sufficient data for evaluation.
Member countries, industry and other data submitters are requested to supply the FAO Panel with all relevant information on identity, metabolism and environmental fate, methods of residue analysis, use patterns (registered and officially authorised uses), supervised residue trials (including field trials and animal transfer studies), fate of residues in storage and processing, residues in food in commerce or at consumption, and national maximum residue limits.
The FAO Joint Secretary of JMPR assigns the compounds for review to the members of the FAO Panel and informs data submitters accordingly. The companies submit the required information to the Panel member, who performs the evaluation of the company's data together with the information received from the member countries through the FAO Joint Secretary before the meeting, and prepares (i) the draft Monograph containing the summarised experimental data and relevant information and (ii) the draft Appraisal containing the evaluation of the results and draft recommendations.
During the Joint Meeting the FAO Panel discusses the evaluations and agrees on the recommendations. The FAO and WHO Expert Groups co-ordinate their activities and, as needed, discuss chemical and toxicological aspects (e.g. metabolism patterns, level and toxicological significance of metabolites), clarify or resolve problematic issues, and finally the groups issue a joint Report containing the conclusions and recommendations of the Meeting.
A short introduction to the assessment process carried out by the FAO Panel follows. A more detailed account of each stage of the process is given in succeeding sections.
In the process of evaluation of a new compound (or periodic review compound), a wide range of information and experimental data are reviewed.
The physical and chemical properties of the active ingredient, the metabolism and degradation of the compound in animals, plants, soil and water are studied to determine the composition and distribution of residues. Based on this information, and taking into account the available analytical methodology as well as the toxicological significance of metabolites and degradation products, the Panel recommends the definitions of residues for enforcement purposes and for dietary intake calculations.
It is emphasised that residues deriving from supervised field trials can only be used for estimating maximum residue levels if the trial conditions can be matched with relevant national GAPs. The maximum residue level estimates are based on already approved national uses (national GAP), which lead to the highest residue populations in the portion of commodities to which Codex MRLs apply (Appendix VI). The JMPR does not approve uses.
The maximum residue levels for residues in commodities of animal origin are mainly estimated taking into consideration the results of animal transfer (feeding) studies and residues occurring in feed items and, to a lesser extent, the information obtained from animal metabolism studies. MRLs for animal commodities may also relate to the residues arising from direct animal treatments.
The analytical methods with accompanying chromatograms and information on stability of residues during sample storage are evaluated to assess the reliability of trial data and to estimate Limits of Determination of residues which can be realistically achieved in regulatory laboratories.
The fate of residues during processing and cooking, as well as residues in the edible portion, are taken into consideration in the estimation of dietary intake.
The results of national monitoring programmes and total diet studies provide useful information, especially for dietary intake estimations, on residues occurring under practical use conditions. Furthermore, the estimation of extraneous residue levels (ERLs, see Section 5.4.3) is based on monitoring data.
The fate of residues in the environment is evaluated to assess the possibility of uptake of residue by the crop (e.g. from a soil treatment) and by following crops, and the contamination of the environment by persistent residues.