The treatment of plants and crops with pesticides may result in residues of these substances in food or drinking water. The issue is to what extent these substances are toxic and can result in health impacts in consumers. The toxicity of these substances is extensively investigated and the determination of threshold values such as the acceptable daily intake (ADI) is based on these studies. The comparison of ADI with exposure data calculated on the basis of occurrence data and consumption data is performed by food safety agencies or authorities such as ANSES (Agence nationale de securite sanitaire de ('alimentation, de l'environnement et du travail) and EFSA (European Food Safety Authority). Given the very low levels of exposure to pesticide residues, these assessments conclude that there are no safety concerns with pesticide residues in food. Nevertheless, an analysis of the hazard characterization process reveals some uncertainties that could in some cases lead to an underestimation of risk, particularly because of insufficient knowledge about the effects of low-dose pesticide mixtures.