Risk assessment of mixtures in the food chain

Many chemicals are present in food as a result of involuntary contamination or resulting from voluntary addition, for example, pesticide or veterinary drug residues, or additives. Assessment of the health risk associated with combined exposure to multiple chemicals from food presents many issues. From the toxicological side, the main question is the identification of the compounds to include in a group for which to assess combined risk. Different criteria have been developed that resulted in groups of compounds of different sizes. Intake can be assessed with increasing levels of refinement, which require increasing levels of resources, in order to identify the occurrence of combined exposures. Assessments have been carried out so far for a number of groups of pesticide residues which resulted in estimated intakes that did not raise concern. However, there is a need for international harmonization of methodologies, especially in those fields where international food trade is involved.