Exposure assessment
Estimates of dietary intakes of food additives, residues of pesticides and veterinary drugs and contaminants require information on the consumption of relevant foods and the concentrations of the chemical of interest in those foods. In general, three approaches are available in exposure assessment: (1) total diet studies (2) selective studies of individual foods, and (3) duplicate portion studies. Guidelines for the study of dietary intake of chemical contaminants are available from WHO. In recent years, direct monitoring of human tissues and body fluids has been increasingly used to assess exposure. For example, the determination of levels of organ chlorine compounds in breast milk, which are mainly derived from the diet, has provided an integrated assessment of human exposure to these substances.