In the U.S., the Interstate Shellfish Sanitation Conference (ISSC) and the Food and Drug Administration (FDA) establish methods of toxin analysis to regulate shellfish, and the National Shellfish Sanitation Program (NSSP) adopts these methods. Currently, there are no methods approved by the ISSC or adopted by the NSSP to detect Diarrhetic Shellfish Poison (DSP) toxins. We are working to increase ISSC validated options for monitoring DSP toxins in support of state and local shellfish managers.

Why We Care
DSP toxins pose a substantial economic threat to shellfish industries globally, and present a major food safety issue for shellfish consumers worldwide. Dinophysis, a species of planktonic dinoflagellate, produces the majority of the DSP toxins found along the U.S. coast. Filter-feeding bivalves accumulate these toxins. Once considered rare in both U.S. and Canadian waters, DSP outbreaks are occurring with greater frequency around the coast of North America.

What We Are Doing
In the U.S., the ISSC and the FDA establish methods of toxin analysis to regulate shellfish, and the NSSP adopts these methods. Currently, there are no methods approved by the ISSC or adopted by the NSSP to detect DSP toxins. This puts the onus on state agencies to develop strategies, based on “best available science,” to monitor shellfish DSP toxin levels and restrict shellfish harvesting as needed. Our primary aim is to increase the number of ISSC validated options available to government regulatory agencies and associated laboratories to monitor DSP toxins, and to promote the inclusion of these methods in the monitoring and management systems used to ensure shellfish safety for the public.

The project team will evaluate three, common DSP-toxin analytical tools for potential ISSC validation:

• a lateral flow immunoassay (LFI) test,
• a phosphatase inhibition assay (PP2A), and
• a Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS) approach.

These methods vary in their levels of quantitation, ease of use, cost, and analysis time, providing a range of options for their use as monitoring tools. The team will use all three methods on DSP toxin–containing shellfish samples from around the North American coast to develop a database of comparable DSP toxin data. The team’s evaluation of these results will inform proposals for the ISSC validation process. In the final year of the project, the team will hold training workshops at the Bigelow Laboratory for state managers interested in using these methods. The outcomes of this project will enhance the capacity of state and local regulatory agencies to manage the increasing threat of DSP outbreaks around the U.S.

Dr. Steve Archer of the Bigelow Laboratory for Ocean Sciences leads this project along with co-lead Dr. Jill E. MacLeod of the Maine Department of Marine Resources. The project is funded through the NCCOS Prevention, Control, and Mitigation of HABs (PCMHAB) Program.