Evaluation of the sampling procedure adopted by the EU pesticide residue control programme to assess consumer exposure to high acute toxicity pesticides: Methamidophos in sweet peppers

Food chemical control, particularly control involving the analysis of pesticide residues in fruits and vegetables, is routinely performed on composite samples. This sample design is adequate for the control of the majority of pesticides which have only long-term effects. However, from the viewpoint of consumer risk assessment, this sample design is inadequate for pesticides with relevant acute toxicity, when their residues occur in large food items the consumption of which may represent an important fraction of a single meal or an important fraction of the consumption in 24 h. This work presents the results of the Portuguese official pesticide residue control authority concerning the variability of methamidophos concentration in sweet pepper units, collected from the market, in the framework of the EU 1999 co-ordinated programme for the official control of pesticides in products of vegetable origin. The results were expressed with uncertainty and the conclusion was that the observed dispersion cannot be allocated to the method precision. The studied samples presented a variability factor (ratio between the maximum and the mean concentration of the units) ranging from 1.8 to 3.5 supporting the need to consider a variability factor representing the potential unit-to-unit variation in residues concentration for the purpose of consumer risk assessment.