Food safety

GEMS/Food total diet studies - joint USFDA/WHO international workshop in cooperation with the Pan American Health Organization



National authorities have the responsibility and obligation to ensure that toxic chemicals, such as pesticides, heavy metals, environmental contaminants and naturally occurring toxins, are not present in food at levels that may adversely affect the health of consumers. While monitoring for compliance with regulatory standards is essential for consumer protection and facilitation of trade, governments need to assess public health risks arising from the presence of toxic chemicals in food by estimating the actual dietary intake of contaminants for comparison with their corresponding toxicological reference intakes, such as the acceptable daily intake (ADI) or provisional tolerable weekly intake (PTWI).

Thus, estimation of the actual dietary intake of contaminants is essential for risk assessment and can also be used in determining whether there may be a relationship between observed adverse effects in humans and exposure to a particular contaminant. Contaminant exposure assessments are equally critical for making sound decisions in the regulation of chemicals and food safety. The Agreement on the Application of Sanitary and Phytosanitary Measures of the World Trade Organization requires that health and safety requirements related to food must be based on sound scientific risk assessment. Consequently, dietary intake estimates should be given greater emphasis by countries not only in the development of national legislation, but also in the context of the Codex Alimentarius Commission and its standards, guidelines and other recommendations. Finally, such estimates provide assurance that regulatory systems that have been established are effective in protecting the public health.

While there are three basic approaches for dietary intake, the total diet study provides, in general, the most accurate estimates of intakes of contaminants for a country as a whole than either of the other methods. In addition, total diet studies explicitly take into account the kitchen preparation of foods to assess the levels of contaminants in foods as consumed. One of the advantages of total diet studies is that they produce information that is readily understandable for use by regulatory agencies, decision-makers and the public. Consequently, there is a growing interest by countries in conducting total diet studies. Such studies, however, are complex, expensive and technically demanding.