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Chester, Canada

DeGrasse S.,U.S. Food and Drug Administration | Conrad S.,U.S. Food and Drug Administration | DiStefano P.,U.S. Food and Drug Administration | Vanegas C.,U.S. Food and Drug Administration | And 10 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography

Paralytic shellfish poisoning (PSP) is the foodborne intoxication associated with the consumption of seafood contaminated with naturally occurring neurotoxins known as paralytic shellfish toxins. To protect public health from this potentially fatal syndrome, harvesting closures are implemented when toxins exceed the regulatory action level. Traditional monitoring programs established by state shellfish authorities allow for timely closures in state waters with minimal negative impacts on industry. However, such monitoring programs are not feasible in federal offshore waters given their distance from shore and the range of their spatial coverage. Thus innovative management strategies were investigated for these offshore resources. Georges Bank, an offshore resource with an estimated market value of more than $3 billion in Atlantic surfclams and ocean quahogs, has been closed to harvesting following a temporary ban in 1989 and a subsequent indefinite closure in 1990 due to the risk of PSP. As a means of managing this risk and allowing harvest of safe shellfish from this important resource, the Onboard Screening Dockside Testing Protocol (referred to as the Protocol) was developed by the US Food and Drug Administration (FDA), National Marine Fisheries Service (NMFS), state shellfish control authorities, and industry. The Protocol, which sets forth control measures to ensure product safety and public health protection, was endorsed by the Interstate Shellfish Sanitation Conference (ISSC) for pilot testing. Briefly, the pilot study Protocol required that (1) the fishing vessel receive a permit from NMFS to harvest in closed waters, (2) a minimum of five shellfish samples per intended harvest lot be tested for PSP toxins onboard, and (3) harvesting only occur when the samples tested from the intended fishing area are negative using the Jellett Rapid Tests or Abraxis Shipboard ELISA kits. Finally, product landed under the Protocol was confirmed to be safe for consumption using the mouse bioassay (MBA) prior to its introduction into commerce. This paper presents data from the pilot study, with primary focus on the advantages and challenges of the field kits employed onboard compared to the dockside MBA, which has served as the longstanding regulatory method for PSP toxins. In 2010 alone, the successful pilot study resulted in the safe harvest of over $2.7 million worth of surfclams in an area that has otherwise been unavailable for decades. Due to the success of this pilot study, the Protocol was adopted into the National Shellfish Sanitation Program Model Ordinance as an approved marine biotoxin control strategy for use in federal waters at the 2011 ISSC Biennial Meeting. In January 2013 a portion of Georges Bank was reopened for the harvest of Atlantic surfclams and ocean quahogs to fishermen following the Protocol. © 2014. Source

Laycock M.V.,Jellett Rapid Testing Ltd. | Anderson D.M.,Woods Hole Oceanographic Institution | Naar J.,Center for Marine Science Wilmington | Goodman A.,Center for Marine Science Wilmington | And 7 more authors.

Over the last several decades, countries throughout the world have experienced an escalating and worrisome trend in the incidence of harmful algal blooms (HABs). A concern is that highly potent algal toxins might be retained in the treated water, posing a threat to human health. Seawater contaminated with saxitoxins, domoic acid, okadaic acid, and brevetoxins was desalinated using small (<100mL capacity) reverse osmosis and distillation equipment. Analyses of desalinated water samples indicated efficient removal of the four toxins to greater than 99%, except brevetoxins for which some carry-over was observed during distillation. Hypochlorite concentrations of 4ppm or higher were sufficient to react with all of the saxitoxins, domoic acid and okadaic acid in the samples that contained initial toxin concentrations up to 1250ngmL -1. Brevetoxins appeared to be unaffected in experiments in which the toxins were exposed to up to 30ppm hypochlorite in seawater at 35°C for 60min. These results and their implications in terms of desalination plant design and operation are discussed. © 2012 Elsevier B.V. Source

Laycock M.V.,Jellett Rapid Testing Ltd. | Donovan M.A.,Jellett Rapid Testing Ltd. | Easy D.J.,Jellett Rapid Testing Ltd.

We have investigated some characteristics of antibodies in the lateral flow format for detecting paralytic shellfish poisoning (PSP) toxins and compared them with the mouse bioassay (MBA). The MBA is still the most reliable test for toxicity in shellfish because it provides an estimate of toxicity directly and can include more than one contaminant. Most other methods, including those involving antibodies, provide estimates of toxin concentration from which toxicity is implied or calculated using conversion factors. Antibody methods suffer from an additional deficiency as sensitivities to the different PSP analogues are unequal. Furthermore, these differences in cross-reactivity are unrelated to differences in specific toxicities. We have addressed the question of what is the toxicity of a sample at the limit of detection (LOD) of the Jellett Rapid Testing Ltd (JRT) lateral flow immunochromatographic (LFI) test. A way to calculate sensitivity to toxicity from toxin profiles is presented and used to examine a variety of PSP toxin mixtures. The calculated values for the sensitivity of the JRT (toxicity at the LOD) for separate PSP toxin analogues may vary over a wide range, but for complex mixtures, typical of natural samples, the range is much narrower. An analysis of PSP toxin profiles of 339 samples from Alaska, Britain, Canada (BC), and USA (Maine) shows the distribution of calculated toxicities at the LOD. The majority (76%) falls within the range 20-50 μg STX eq/100 g with a mean at 32 μgSTXeq/100 g which is similar to that of the MBA. Observed data from independent parallel studies with the JRT and MBA with a total of 3492 samples from regulatory laboratories in different countries in the period 2003-2007 show close agreement between the two methods. All samples that were found to be positive with the MBA were also positive with the JRT except for one which indicated a false negative rate of less than 0.03% of all samples tested. The JRT for PSP was designed to be more sensitive than the MBA in order to be used as a screen to reduce the high proportion of negative samples encountered in routine monitoring. Toxicity at the LOD varies depending on the mixture of PSP toxins and false positives are therefore inevitable. In this study false positives accounted for between 1.4% and 55% of the total number of samples tested. This would also depend on whether contamination was endemic or rare in the different locations. The data from regulatory monitoring for PSP show that in all areas the majority of samples are negative and so the use of a screen would result in a significant reduction in the use of mice. © 2009 Elsevier Ltd. All rights reserved. Source

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