Speeding Safer Shellfish

A new test for dangerous shellfish toxins, developed by scientists at Queen’s University in Belfast, Ireland, speeds up the usual process for detecting these toxins from about 48 hours to 30 minutes.

Paralytic shellfish poisons (PSPs) are among four primary types of shellfish poisoning caused by toxins produced by microscopic algae that accumulate in bivalves like clams, mussels, oysters, and scallops. Although such instances of poisoning are rare, consuming enough of the toxin can lead to paralysis of the chest and abdominal muscles, choking off breathing. According to a report from Washington State University, worldwide, death rates from PSP poisoning have been estimated at 15%.

“There is growing evidence that climate change is causing many more toxic episodes across the world, resulting in the closure of affected shellfish beds,” said test developer Chris Elliott, PhD, who is also director of the Institute of Agri-Food and Land Use at Queen’s University School of Biological Sciences in Belfast.

In the lab, Dr. Elliott’s team developed specialized antibodies designed to bind specifically to the shellfish toxins. “The more toxic the molecule, the tighter they bind,” he said. “The test has not been commercialized yet, so it’s difficult to estimate a cost saving, but I think it’s fair to say that it will be more than 75% cheaper than the current cost per sample to use this assay.” In the U.S., current methods cost about $25 per test.

It took nearly six years of research to develop the test, Dr. Elliott said. “We had to develop a fundamental understanding of the toxins from both a point of view of their chemistry and mode of action,” he said.

The next step will be to adapt the sensor test by transferring it onto a dipstick-type device. To do this, the researchers will collaborate with Neogen Corporation, a company in Lansing, Mich., that focuses on developing products related to food and animal safety. “We expect to have a device ready for the market within the next 12 months, but we will have prototypes ready much sooner than this and welcome any interested party to contact us to become involved in working with these devices to assess their performance,” Dr. Elliott said.

He added that he expects to publish the current validation study later this year. A March 2010 paper in Analytical Chemistry initially described the work (Anal. Chem. 2010, 82;(7):2977–2988.

“The test will not only make shellfish safer to eat, but it will also have a significant impact on global aquaculture industries as they struggle to deal with the rising problems of toxins caused by climate change,” he said.

The researchers have also received a $500,000 grant from the U.S. Food and Drug Administration to further develop the test in the U.S. so that it can be conducted in laboratories and on boats as soon as the shellfish are caught, drastically reducing the time it takes to get the catch from fishing nets to supermarket shelves.

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