HBGVs and BMDLs

Terms

Exposure assessments for food and feed compare intake values with HBGVs. "HBGV" is an acronym for Health Based Guidance Value, and it is synonymous with the maximal permissible health based exposure of a consumer to a chemical substance. In some literature one can find the former term "norm" for these values. This term is sometimes causing confusion, as a HBGV is not a legal standard but a toxicological guideline value. The term Reference Value is used in North America for a value describing the maximal permissible exposure to chemical substances for exposed individuals, but it can easily be misunderstood, as a Dietary Reference Value refers to recommended nutritional requirements.

Exposure assessment

As HBGVs describe the maximal permissible exposure, they are widely used in exposure assessments of chemical substances in food and feed. Its concept is that an actual exposure to a chemical substance should not exceeds the appropriate HBGV. This concept originates from the sixties of the previous century and is being used today in food safety risk assessments. When the exposure exceeds its HBGV, then the food or feed is considered "unsafe" for consumption, e.g. in line with the EU Regulation 178 of 2002, article 14. And it can be concluded that one is dealing with a "serious" or "unacceptable" risk for consumers. According to the EU Regulation unsafe food or feed can not be traded; in this way the consumers are protected against adverse effects from these chemical substances.

Margin of Exposure

A more recent exposure assessment concept replacing the use of the HBGV is the Margin of Exposure of EFSA. This concept was published in 2012 to evaluate exposure to genotoxic and carcinogenic substances. Here the exposure should be compared with a BenchMark Dose Limit (BMDL). EFSA noted that the lifetime exposure to genotoxic carcinogens should be 10,000 times lower than that of the BMDL10 for animals. The method of how a BMDL is derived differs from that of a HBGV. This will be explained in the following pages. Consequently, it must be understood that a BMDL is not synonymous with the maximal permissible exposure as the HBGV is. So a BMDL is not a HBGV.