Sleuthing for toxins keeps Canada's seafood supply safe

Lobster supper in the Canadian Maritimes. Scallops at a chic bistro in Paris, France. Oysters on the half shell at restaurants in Sydney, Australia.

What do all these dishes have in common? They are safe to eat because methods and reference materials developed in Canada have shown they are free from harmful toxins. In more than 60 countries around the world, shellfish and other foods are examined regularly for toxins using methods based on certified reference materials (CRMs)—the gold standard for biotoxin measurement—researched and developed by the National Research Council of Canada's (NRC) Metrology Research Centre. Recognized internationally as the world's top analytical chemistry lab for marine and freshwater toxins, the Biotoxin Metrology team based in Halifax, Nova Scotia has developed nearly 40 biotoxin CRMs that are used daily in Canada and elsewhere.

Marine animals, including shellfish and other seafood, feed on natural algae as an essential food source. However, occasionally there are blooms of algal species that naturally produce chemicals (toxins) that are harmful to humans. The seafood can accumulate these toxins to levels that pose risks to human health, which can lead to issues such as headaches, nausea, gastrointestinal problems, organ damage, and even death.

"Since the beginning of the toxin research program at the NRC in the 1980s, a fundamental focus has been on understanding the biology of harmful algae," says the NRC's Pearse McCarron, Team Leader, Biotoxin Metrology. "With this knowledge basis we have been able to advance our understanding of biotoxin chemistry and in turn, develop cutting-edge analytical methods for measuring toxins produced by algae."

This work has also led to research activities that investigate threats not previously considered. For example, tetrodotoxin (TTX)— a deadly neurotoxin most commonly found in pufferfish that normally inhabit tropical waters—has been shown at potentially harmful levels in shellfish in Europe and the U.K.

"We have just completed a very successful project with the Canadian Food Inspection Agency (CFIA) to develop analytical tools to help evaluate whether this neurotoxin has moved into Canadian waters and if it poses a risk to our shellfish,".

Partners in progress

With collaborators in Canada and around the world, the Biotoxin Metrology team successfully leverages internal expertise with external resources to help solve problems quickly to ultimately ensure consumer safety. In Canada, these include the CFIA and Health Canada, which are considered essential services.

According to Cory Murphy, the CFIA's Chemistry Section Manager, collaborative efforts with the Biotoxin Metrology team date back to the 1980s. "While our 2 groups have many formal agreements, our longstanding relationship allows us to work informally as well—picking up the phone if something rings alarm bells, sharing equipment and leveraging complementary skills." Wade Rourke, Unit Supervisor, CFIA adds that his agency provides the NRC with access to a large number of research samples across the country that yield ongoing data to help keep CRMs updated.

One major collaboration between the NRC and CFIA led to a disruptive testing methodology that has now been adopted across the globe. "This was a move away from animal testing into chemical analysis," says Rourke. "Animal assays often produce false positives and negatives, whereas modern chemical analytical techniques are more reliable. They also provide more detailed information that can be used to flag danger at an earlier stage."

At the core of the NRC's success in the field of toxins lies the expertise of the team's 15 members. "Having a range of disciplines and capabilities within one team puts us in a unique position in Canada and internationally to address a wide variety of the challenges posed by algal toxins," says McCarron, pointing out that their work is recognized worldwide. The team also routinely hosts laboratory visitors and trains international students and researchers.