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The Committee on Toxicity report 'Risk assessment of mixtures of pesticides and similar substances', published in 2002, made some recommendations, including one for research to be conducted into the effects of processing and preparation on the bioavailability and chemical nature of residues. This work is required to enable realistic assessments of exposure, and thereby risk, from mixtures of pesticides in the diet, and from pesticides and similar substances from all sources and pathways combined.
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An FSA-funded project has already assessed the effects of storage time, washing processes, peeling and various cooking methods on residue levels of a small selection of pesticides in certain types of apples and potatoes.
pathways combined.
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This new project will assess additional pesticides in additional foods, focusing on pesticide residues that are most commonly detected in UK surveillance, which belong to groups of pesticides with pesticides with similar toxic actions, and where data gaps on the effects of processing exist.
pathways combined.
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Objectives:
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Validate standard operating procedures (SOPs) for the determination of the selected pesticides and associated metabolites (where authentic standards are available) in the 11 agreed commodities (cabbage (winter & summer), broccoli, tomato, carrot, celery, parsnip, dwarf bean, raspberry, Plum and pear).
</LI> <LI> Grow relevant crops and treat with agreed dosage of pesticide suite pre- and post-harvest based on modified good agricultural practice.
</LI> <LI> Determine and compare the quantities of residues (including metabolites where available) in washed and unwashed raw produce and after preparation and processing, using analytical methods validated in objective 1.
</LI> <LI> Statistically evaluate the experimental data. </li></ol>
Methodology:
Appropriate SOPs for the preparation and processing of the various fruit and vegetables intended for use in this study will be developed for use. A combination of GC-MS and LC-MS instrumental techniques will be used to quantify residue levels in solvent extracts from representative samples of each commodity pre- and post-processing, spiked with pesticides of an appropriate range and concentration, and involving sufficient analytical replication to ensure good recovery and precision of analytical methods.
A statistically valid experimental plan (designed in conjunction with Applied Plant Science and Biometrics Division, AFBI) will be followed to ensure a sufficient and timely supply of treated fruit and vegetables that will facilitate sufficient randomisation and replication of samples to detect any statistically significant differences in residue levels between treatments, according to OECD Guideline 508. Following preparation, representative samples will be stored deep-frozen prior to analysis.
pathways combined.
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Analyses will be carried out using the standard analytical methods validated at the beginning of the study.
pathways combined.
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The effects of washing and processing will be evaluated by analysis of variance (ANOVA) using GenStat with Fisher’s protected least significant difference (LSD), in order to detect statistically significant differences in residue levels due to preparation and processing.pathways combined.
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<p>Find more about this project and other FSA food safety-related projects at the <a
href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research
webpage</a>.