Food safety

Global Environment Monitoring System - Food Contamination Monitoring and Assessment Programme (GEMS/Food)


Acute and chronic dietary exposure to chemicals in food

Exposure assessment is an essential element for quantifying risk. The role of dietary exposure assessment has been central to the work of the Joint Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) and the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) in performing risk assessments on chemicals in foods.

Dietary exposure assessment combines food consumption data with data on the concentration of chemicals in food. The resulting dietary exposure estimate may then be compared with the relevant health based guidance value for the food chemical of concern, if available, as part of the risk characterization. Assessments may be undertaken for acute or chronic exposures, where acute exposure covers a period of up to 24 h and long-term exposure covers average daily exposure over the entire lifetime.

The general equation for both acute and chronic dietary exposure would be expressed as follows:

Formula

International estimated short-term intake (IESTI)

International Estimated Short-term Intakes (IESTIs) are assessed for a pesticide by the Joint FAO/WHO Meetings on Pesticide Residues (JMPR) when it has established (or intends to establish) an acute reference dose (acute RfD) for the pesticide. Exposure is calculated by multiplying the highest residue values by the highest 97.5th percentile of food consumed on a single day.

International Estimated Daily Intake (IEDI)

International Estimated Daily Intakes (IEDIs) are assessed for a pesticide by the Joint FAO/WHO Meetings on Pesticide Residues (JMPR). Exposure is calculated by multiplying the median concentrations of residues (STMRs and STMR-Ps) by the average daily per capita consumption estimated for each commodity on the basis of the GEMS/Food Consumption cluster diets. IEDIs are expressed as a percentage of the ADI for a 55 kg or 60 kg person, depending on the cluster diet.

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