Sécurité sanitaire et qualité des aliments

Study sets four sub-Saharan African countries on track to reduce chemical contaminants in food


When tested for 800 chemical residues and contaminants, as part of an FAO study, in most cases, the exposure from food consumed in Benin, Cameroon, Mali and Nigeria did not exceed levels of toxicological concern. However, the study also revealed that several mycotoxins, lead, aluminium, polycyclic aromatic hydrocarbons and a pesticide could be a cause of concern for households in some areas of each of the four African countries.

The findings of this large-scale total diet study, conducted by FAO with technical support of the World Health Organization and Centre Pasteur of Cameroon, are detailed extensively in an article published by The Lancet Planetary Health on 16 July 2020.  

“We saw vastly different levels of exposure for some of the chemicals, even between two locations of the same country,” said Luc Ingenbleek, FAO Food Safety Consultant, attributing the contrast to variations in diet as well as chemical concentration. “By studying more than 90 percent of the foods people consume, we can see exposure patterns,” he said in explaining the effectiveness of a total diet study in assessing chemical exposure.

To determine chemical exposure, the food expenditures of more than 7,000 households were examined and more than 4,000 food samples tested at four laboratories.

It’s all in the amount

On a daily basis, people consume chemicals, which in most cases are harmless. Five centuries ago Paracelsus, who can be considered the father of toxicology, wrote: Sola dosis facit venenum, meaning that only the dose makes a substance a poison, explained Jean-Charles Leblanc, FAO Lead Technical Officer. Chemical hazards in food can affect human health if the amount ingested exceeds what is referred to as the “level of toxicological concern,” specified Markus Lipp, FAO Senior Food Safety and Quality Officer and Joint FAO/WHO Expert Committee on Food Additives (JECFA) Secretary.

What’s next?

The four countries involved in the study have already drafted roadmaps to carry out specific action plans. FAO has started to mobilize funds to work with the Government of Mali to improve the smoked fish value chain, which was identified as a contributor to exposure to polycyclic aromatic hydrocarbons and to one pesticide, affirmed Blaise Ouattara, Food Safety and Quality Officer at the FAO Regional Office for Africa.

This project and its continuation show how the findings of a risk assessment can be used to better manage risks. 

The Total Diet Study was funded by the Standards and Trade Development Facility.  

Watch the video in English, French, Spanish

Listen to the Codex podcast segment


Read more in:

  The Lancet Planetary Health 2020 

  Environment International 2020a

  Environment International 2020b

  Environment International 2019

  Food Chemistry: X 2019

  Food Control 2019

  Toxins 2019  

  Food and Chemical Toxicology 2017

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