Food-producing animals are exposed to toxic micropollutants via their environment and feeds. These micropollutants represent a chemical human health hazard because they are capable of entering the animals and being transferred to edible tissues 1 . Most current approaches to assessing contamination levels in foods are based on high performance analytical methods designed to determine the concentration of targeted micropollutant residues present down to trace levels in the food. Alternative analytical approaches have been proposed that consist of seeking indirect markers of exposure to micropollutants, e.g. metabolites such as lipids, amino acids, simple sugars or cofactors.