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Better detecting foodborne toxins of marine origin

Each year, worldwide, tens of thousands of people get food poisoning from seafood products. Hélène Martin-Yken is a scientist in INRA's Joint Research Unit for the Engineering of Biological Systems and Processes (LISBP). She and her team performed a study aimed at improving tools for detecting foodborne toxins of marine origin, which are the primary cause of seafood-related food poisoning. The results were published in Environmental Research.

Better detecting foodborne toxins of marine origin. © INRA, Franck Ludi Photographie
Updated on 10/18/2018
Published on 02/23/2018

Of the various illnesses caused by seafood consumption, ciguatera fish poisoning is the most common worldwide. Ciguatera is not a new disease—the explorers Cook and Vasco da Gama both fell ill from this form of fish poisoning. While ciguatera has always been especially prevalent in the tropics and subtropics, it has progressively spread to more temperate regions, like Europe, notably because of climate change.

Around 30 years ago, researchers discovered the cause of the disease: microalgae in the genus Gambierdiscus that tend to proliferate in disturbed areas, particularly those in which coral reefs have suffered because of pollution or global warming. These plankton produce extremely potent neurotoxins: ciguatoxins (CTXs). When fish and shellfish eat the plankton, they also ingest the CTXs. These toxins bioaccumulate along the food chain and can reach high concentrations in large fish, including the most commonly caught species. When humans consume CTX-contaminated fish or seafood, they can become ill with ciguatera; symptoms can last several weeks or even months. An additional challenge is that these toxins cannot be destroyed by cooking or freezing.

CTXs were the subject of a research study led by Hélène Martin-Yken, a LISBP researcher. This work was carried out as part of a collaboration with scientists from the Laboratory of Toxic Microalgae (LMT), which is affiliated with the Louis Malardé Institute and the French Research Institute for Development in French Polynesia. The study’s findings were published in the journal Environmental Research.

Some of these researchers have long been working with yeasts, which are frequently employed as biological models and study tools because yeast cells share strong similarities with human cells. The idea arose to use the yeast Saccharomyces cerevisiae to detect the presence of toxins. The research team showed that, even at high concentrations, CTXs were not toxic to yeast cells. However, the yeast species could sense and respond to the CTXs, which means it could potentially be used to determine toxin presence and abundance.

These findings may greatly contribute to improving methods for detecting CTXs in seafood, as current tools are both expensive and time intensive. The use of yeast cells could make it easier to detect these toxins and thus, ultimately, more rapidly control outbreaks of foodborne illnesses.

At present, the researchers are working to increase the sensitivity of their tests to render them even more effective.

Find out more

Ciguatoxins activate the Calcineurin signalling pathway in Yeasts: Potential for development of an alternative detection tool? H. Martin-Yken, C. Gironde, S. Derick, H.T. Darius, C. Furger, D. Laurent, and M. Chinain. Environ Res. 4 Jan 2018 (162): 144-151. DOI: 10.1016/j.envres.2017.12.022.