Approaches in measuring exposure to food contaminants.

Measurement of levels of contaminants in food commodities and prepared meals, and market basket surveys are feasible in countries with existing systems of food control laboratories. Monitoring body tissues for contaminants or their metabolites reflects total exposure but care should be taken to select the most appropriate pharmacokinetic model.Strict quality control acquires particular value in obtaining (with existing instrumentation and facilities) results that meet specified acceptable parameters of analytical performance.Exposure measurement of dietary contaminants as a part of epidemiological studies becomes indispensable in the risk assessment process. Dietary intakes of DDT in USA and Bulgaria are within the range of 'virtually safe doses' for liver tumors extrapolated from animal experiments by four low dose extrapolation models for risk levels of 10(-4) and 10(-6).