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Tracking down unknown food contaminants

Chemical contaminants are everywhere: in cities, in farmers’ fields, in nature, and ultimately, on our plates! In fact, there are thousands of them in food, not to mention others that have yet to be discovered… To identify these unknown or undetected chemical substances using current analytical methods, Stéphane Bayen, a researcher and professor in McGill University’s Department of Food Science and Agricultural Chemistry, has adapted a molecular analysis tool called “high-resolution mass spectrometry”. He has drawn on advances in analytical chemistry and algorithms to develop a so-called “non-targeted” analysis approach, which can find a needle in a haystack. In this way, the researcher wants to contribute to the mapping of food contaminants, a valuable bank of information for better protecting the health of populations.

Thanks to his innovation, Stéphane Bayen and his team have been able to detect traces of new molecules, probably contaminants, in fish livers, bread, honey and chicken, among others, that should not be found in these foods. They also found traces of veterinary drug residues, such as antibiotics, mainly in imported seafood.

The new high-precision, non-targeted screening tool was also used to understand the effect of cooking on contaminants. The literature shows that the levels of many chemical contaminants decrease when a food is cooked, but the analytical chemistry expert knows that molecules do not simply disappear: they are transformed. Into what? In collaboration with Céline Audet, a researcher at the Institut des sciences de la mer de Rimouski at UQAR, Stéphane Bayen was able to show that after cooking, contaminated farmed trout did indeed contain new chemical molecules.

But are all the substances identified by this innovative method a cause for concern? Since he is not a toxicologist, Stéphane Bayen is working with chemical risk experts from Health Canada and the Canadian Food Inspection Agency. While awaiting their verdicts, the researcher is pursuing his search for unknown contaminants.