Finding diarrhetic shellfish poisoning faster

Mussels, oysters, scallops and clams might be ingredients for fine cuisine, but they can also be a recipe for diarrhetic shellfish poisoning (DSP) — a gastrointestinal illness caused by marine toxins. Now, a portable, inexpensive device has been developed that can quickly and easily screen freshly caught shellfish for these toxins.

DSP is caused by eating shellfish that have accumulated okadaic acid (OA) or related marine toxins. Algal blooms — commonly referred to as ‘red tides’ — can produce these substances, which shellfish can accumulate through filter feeding. Because cooking the shellfish does not destroy the toxins, several regulations are in place to prevent the sale and consumption of tainted shellfish. To comply with these regulations, the current practice is to send samples to labs that use expensive, technically intense and slow tests.

So researchers set out to develop an inexpensive, easy-to-use and portable device that maintained the rigorous testing standards of off-site labs but could quickly test shellfish on boats and at other remote locations.The device’s development was led by researcher Waqass Jawaid, a scientists with diagnostics company Neogen Europe and Queen’s University’s Institute for Global Food Security.

The researchers adapted a test called a lateral flow immunoassay (LFIA), which is like a home pregnancy test strip. This LFIA combines simple test procedures with an antibody previously shown to specifically bind to three OA toxins. The small, portable device can accurately screen for the presence of these substances in less than 20 minutes on a boat, before it goes further into the supply chain. If the test is positive, then the shellfish would not be sold. If the LFIA readout is negative, then an additional, easy-to-use test could be conducted dockside for ‘total toxins’, which would include detection of a fourth type of OA.

The researchers have published their results in the Journal of Agricultural and Food Chemistry and also acknowledge funding from Innovate UK, Scottish Enterprise and Neogen Europe.