Contamination Of Shellfish Research Articles

Occurrence of legacy and emerging halogenated organic contaminants in marine shellfish along French coasts

Current contamination levels of selected legacy, currently-used and emerging halogenated contaminants were monitored in marine shellfish along French coastlines. The studied contaminants included polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE), hexabromobenzene (HBB), 2,2′,4,4′,5,5′-hexabromobiphenyl (BB-153) and perfluorinated compounds (PFCs).BDE-47, BDE-209, BTBPE, HBB and α-HBCDD were detected in 100% of the analyzed samples, whereas BB-153, DBDPE and PFOS were detected at frequencies of 97%, 90% and 55%, respectively. Concentrations were in the pgg−1ww range and varied as follows: PFOS>BDE-47∼α-HBCDD>BDE-209>BTBPE∼DBDPE>HBB∼BB-153. Overall, non-PBDE Brominated Flame Retardants (BFRs) revealed concentrations between 3 and 59 times lower than those of PBDEs.PBDE pattern was dominated by BDE-47, followed by BDE-99>BDE-100>BDE-49>BDE-209>BDE-154; these 6 congeners represented 94% of the summed ten PBDEs. PFC pattern determination revealed PFOS as the predominant PFC in samples from the English Channel and Atlantic, whereas perfluorocarboxylic acids (PFCAs) prevailed in Mediterranean samples. Temporal trend investigations on archived samples from the Mediterranean coast collected between 1981 and 2012 showed a prevalence of PFOS until 1998; PFCAs subsequently increased and became more abundant than PFOS. High levels of PFCAs were observed until 2008, followed by a decrease and stabilization in 2010–2012. Amongst PFCAs, perfluorotridecanoic acid (PFTrDA) and perfluoroundecanoic acid (PFUnA) were predominant and exhibited similar time trends, suggesting similar sources at the investigated site, home to major industrial activity.

Are fecal stanols suitable to record and identify a pulse of human fecal contamination in short-term exposed shellfish? A microcosm study

In this study, the capacity of oysters to bioaccumulate fecal stanols and to record a source-specific fingerprint was investigated by the short-term contamination of seawater microcosms containing oysters with a human effluent. Contaminated oysters bioaccumulated the typical fecal stanols coprostanol and 24-ethylcoprostanol and their bioaccumulation kinetics were similar to that of the Fecal Indicator Bacteria Escherichia coli used in European legislation. Although stanol fingerprints of contaminated water allowed the identification of the human specific fingerprint, this was not the case for oysters. This discrepancy is attributed to (i) high concentrations of endogenous cholestanol and sitostanol, responsible for “unbalanced” stanol fingerprints, (ii) different accumulation/depuration kinetics of fecal coprostanol and 24-ethylcoprostanol and (iii) the limits of the analytical pathway used. These results show that fecal stanols bioaccumulated by oysters are useful to record fecal contamination but the usefulness of stanol fingerprints to identify specific sources of contamination in shellfish currently seems limited.

Chlorinated and brominated organic pollutants in shellfish from the Yellow Sea and East China Sea.

The global contamination with persistent organic pollutants (POPs), or compounds with similar characteristics, is well known. Still there are data gaps for POP concentrations from many areas in the world. The aim of the present study is to assess several legacies POPs and also hexabromocyclododecane (HBCDD) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in shellfish from three locations in the Yellow Sea and East China Sea. The sources of the contaminants are discussed. Pooled samples were treated by liquid-liquid extraction and acid and column cleanup prior to analysis by gas chromatogram equipped with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS). The by far most abundant environmental contaminant originates from dichlorodiphenyltrichloroethane (DDT), independent of species analyzed or sampling site. The results indicate ongoing or at least recent discharges of DDT. The second highest concentrations were reported for HBCDD (21–40 ng/g fat) in the shellfish, independent of sampling sites. The two natural products, 6-MeO-BDE-47 and 2′-MeO-BDE-68, were also present in the shellfish (1.3–22 and 1–14 ng/g fat, respectively). The polychlorinated biphenyl (PCB) congener CB-153 (0.8–6.5 ng/g fat), hexachlorobenzene (HCB) (1.1–3.6 ng/g fat), and β-hexachlorocyclohexane (β-HCH) (2.3–4.9 ng/g fat) were all higher than the concentrations of other HCH isomers, β-endosulfan, PBDE congeners, and mirex. Apart from the DDTs and HBCDDs, it is evident that the pollution of shellfish was similar to, or lower than, the contamination of shellfish in other parts of the world.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-014-3198-8) contains supplementary material, which is available to authorized users.

N-Acetylcysteine boosts xenobiotic detoxification in shellfish

Water pollution represents a threat of increasing importance to human health. Bivalve mollusks are filter-feeding organisms that can accumulate chemical and microbiological contaminants in their tissues from very low concentrations in the water or sediments. Consumption of contaminated shellfish is one of the main causes of seafood poisoning. Thus, marine bivalves are normally depurated in sterilized seawater for 48h to allow the removal of bacteria. However, this depuration time might be insufficient to eliminate chemical contaminants from their tissues. We have developed a novel technology that accelerates up to fourfold the excretion rate of xenobiotics in bivalves by treatment with the antioxidant and glutathione (GSH) pro-drug N-acetylcysteine (NAC) during the depuration period. NAC improved dose-dependently the detoxification of the organophosphate (OP) pesticide fenitrothion in the mussel Mytilus galloprovincialis, diminishing its levels up to nearly a hundred fold compared to conventional depuration, by enhancing the glutathione S-transferase (GST) activity and inducing the GSH anabolism (GSH synthesis and reduction by glutathione reductase). Notably, this induction in GSH anabolism and GST activity was also observed in uncontaminated bivalves treated with NAC. As the GSH pathway is involved in the detoxification of many pollutants and biotoxins from harmful algal blooms, we validated this proof of principle in king scallops (Pecten maximus) that naturally accumulated the amnesic shellfish poisoning (ASP) toxin domoic acid. We illustrate here a method that enhances the elimination of organic contaminants in shellfish, opening new avenues of depuration of marine organisms.

Qualitative and quantitative assessment of viral contamination in bivalve molluscs harvested in Italy

Bivalve molluscs are a well documented source of viral infection. Further data on shellfish viral contamination are needed to implement European Regulations with sanitary measures more effective against viral pathogens. To this aim, 336 samples of bivalve molluscs (185 mussels, 66 clams, 23 oysters and 62 samples from other species) collected in harvesting areas of class A and B of four Italian Regions were analyzed for qualitative and quantitative determination of hepatitis A virus (HAV) and Norovirus (NoV) GI and GII, using real time RT-PCR.The results showed a wide diffusion of viral contamination in the shellfish production areas considered. HAV prevalence was low (0.9%) with contamination levels that varied from 5 to 7×102copies/g. On the contrary, NoV showed a high prevalence (51.5%), with a large variability according to the group considered (e.g. 47.8% for Crassostrea in Veneto, 79.7% for Mytilus in Campania, 84.6% for Tapes in Sardinia). NoV contamination affected class A and class B production areas to a different extent, with a statistically significant difference in both contamination prevalence (22.1% vs. 66.3%; p<0.0001) and quantity (average contamination level of 3.1×102 vs. 1.9×103 copies/g; p<0.05). The different species analyzed from class B harvesting areas (Mytilus, Tapes/Ruditapes and Crassostrea) showed a NoV prevalence respectively of 70.3%, 66.0% and 47.8% but comparable NoV contamination levels (between 8.4×102 and 4.9×103copies/g). Other two bivalve species considered in the study (Donax spp. and Solen spp.) showed a relevant NoV presence (40.0% and 34.4% of samples). Finally, samples analyzed before and after commercial purification treatment showed a decrease of contamination prevalence after the treatment, but inconsistent results were recorded on NoV levels.The data obtained, together with other quantitative information to estimate consumer exposure, in association with studies on dose–response and on the effectiveness of post-harvest treatments, will provide a useful tool for the definition of microbiological criteria related to the different shellfish species.

Dinophysis toxins: causative organisms, distribution and fate in shellfish.

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L−1). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

Virus entériques humains et coquillages

Human enteric viruses and shellfish Human enteric viruses discharged in raw sewage are hightly resistant and may be detected in surface waters, coastal areas and shellfish. Whereas noroviruses, responsible for relatively benign acute gastroentritis, are the most common agents implicated in shellfish borne outbreaks, other human viruses which cause severe human diseases, such as hepatitis A virus, may also be transmitted. Environmental studies have demonstrated that virus concentrations detected in shellfish are higher than in surrounding waters. This concentration may explain the high prevalence of noroviruses detected in various shellfish species collected in different countries. If many questions remain regarding viral contamination of shellfish, the most important seems to be the prevention of coastal areas contamination by human sewages.

Concentration of enteric virus indicator from seawater using granular activated carbon

Fecal contamination of shellfish growing seawater with enteric viruses is often associated with human outbreaks of gastroenteritis. Male specific bacteriophage MS2 is correlated with those of enteric viruses in a wide range of water environments and has been used widely as a surrogate for pathogenic waterborne viruses. Since viruses in contaminated water are usually at low levels, the development of methods to concentrate viruses from water is crucial for detection purposes. In the present study, granular activated carbon was evaluated for concentration of MS2 from artificial seawater, and different parameters of the seawater were also compared. Recovery of MS2 from warm seawater (37°C) was found to be significantly greater than from cold seawater (4 and 20°C), and even greater than from fresh water (4, 20 and 37°C); the difference between seawater and fresh water became less profound when the temperatures of both were below 37°C. Although not of statistical significance, recovery of MS2 from low salinity seawater (10 and 20 parts per thousand, ppt) was greater than from high salinity seawater (30 and 40ppt). One gram of granular activated carbon was able to extract 6-log plaque forming units (PFU) of MS2 from 500ml seawater at 37°C. This study demonstrated that granular activated carbon can concentrate an enteric virus indicator from shellfish growing seawater effectively.

Chronic hepatitis E in an immunocompetent patient: A case report

Hepatitis E virus (HEV) is a single-stranded RNA virus in the Hepeviridae family with four major genotypes. Genotypes 1 and 2 are restricted to humans1 with genotype 1 predominant in Asia and genotype 2 in Africa and Mexico. HEV genotypes 3 and 4 infect humans as well as other mammalian species in a worldwide distribution.2, 3 The prevalence of HEV in the U.S. population is 21.0% based on HEV immunoglobulin G (IgG) antibody seropositivity in population-based surveys from 1988 to 1994.3 Reports of chronic HEV infection have been limited to immunosuppressed patients who are human immunodeficiency virus (HIV)-positive, have hematological malignancies, or are solid-organ transplant recipients.4 Reduction of immunosuppression and/or monotherapy with pegylated interferon or ribavirin has shown efficacy in the treatment of chronic HEV infection.1 A study in France of six kidney transplant recipients with chronic HEV genotype 3 infection demonstrated that ribavirin therapy for 3 months led to sustained virilogical response in four patients.5 Here we describe a unique case of chronic hepatitis E, anti-HEV IgG-positive, anti-HEV IgM-negative, HEV RNA-positive in an immunocompetent patient. The patient is a 62-year-old woman who presented in 2005 with persistently elevated alanine aminotransferase and aspartate aminotransferase levels. She had been treated for systemic lupus erythematosus in her 20s with prednisone and plaquenil and remained in remission thereafter. She drank socially and ran 3-4 miles every day. Work-up for viral, autoimmune, and genetic liver diseases was negative. She had a weakly positive antinuclear antibody (ANA) but her immunoglobulin levels were normal. Her initial liver biopsy in 2005 showed a mild nonspecific hepatitis. A trial of prednisone and azathioprine for possible autoimmune hepatitis was discontinued after 7 months due to lack of efficacy. In 2007 her biopsy showed grade 2, stage 2 chronic hepatitis. This progression prompted a second unsuccessful course of oral steroids and azathioprine. A final biopsy in 2009 showed stable hepatitis and fibrosis (Fig. 1A,B). Ursodiol was started. Transient elastography (FibroScan) in 2011 reported a value of 11.2 kPa, correlating with Metavir stage 3 fibrosis. Amid reports of chronic HEV infections in solid organ transplant recipients, the patient was tested for HEV serological markers in December 2011, and while anti-HEV IgG was positive, anti-HEV IgM was negative. Frozen serum was sent to the Centers for Disease Control and Prevention in January of 2012 for IgM and IgG anti-HEV serology and real-time polymerase chain reaction (PCR) for HEV RNA. (http://www.cdc.gov/hepatitis/HEV/LabTestingRequests.htm).6 The sample tested anti-HEV-IgG-positive and anti-HEV IgM-negative. HEV RNA was detected in serum with a titer of 6.2 × 105 IU/L. Sequencing studies determined HEV genotype 3. Based on chronicity of HEV supported by HEV RNA and anti-HEV IgG positivity for ∼5 months and negative anti-IgM along with persistently elevated transaminases, therapy with ribavirin 400 mg twice daily was initiated in April of 2012 with normalization of liver enzymes at 2 months. HEV RNA was undetectable at 4 months. Treatment was discontinued after 6 months and liver enzymes have remained normal to date. The patient denies receiving blood products. She does eat pork, oysters, and mussels. She drinks well water in her rural vacation home. She made several trips to Mexico and experienced an episode of fever and gastrointestinal disturbance upon returning from a trip in 2002. HEV genotype 3 has been isolated in those who consumed pork products, mussels, and game meat.1, 3, 4 Swine-associated HEV strains have been identified in sewage water3 and can lead to shellfish contamination. It is tempting to speculate that this patient may have acquired HEV infection by consuming pork or shellfish. Recent studies in solid organ transplant recipients have shown that acute HEV genotype 3 infection or reactivation in anti-HEV IgG-positive transplant recipients can lead to chronic hepatitis with progression to cirrhosis.4 Our patient also had HEV genotype 3 infection; the distant history of lupus may have predisposed her to the development of chronic HEV infection. This case highlights the importance of suspecting chronic HEV infection in patients with unexplained chronic hepatitis. However, the lack of a standardized commercial nucleic acid-based assay in the U.S. to detect HEV RNA in stool or serum limits testing, although two commercially available RT-PCR RNA assays for HEV genotype 3 are reported in Europe.7 Chronic HEV infections related to genotypes 1 and 2 have not been reported so far. An effective HEV vaccine has been approved in China following a controlled trial in 100,000 volunteers.8 HEV vaccination would be very useful to prevent chronic HEV in immunosuppressed patients and those with chronic liver disease.

Identification of the origin of faecal contamination in estuarine oysters using Bacteroidales and F-specific RNA bacteriophage markers

The aim of this study was to identify the origin of faecal pollution impacting the Elorn estuary (Brittany, France) by applying microbial source tracking (MST) markers in both oysters and estuarine waters. The MST markers used were as follows: (i) human-, ruminant- and pig-associated Bacteroidales markers by real-time PCR and (ii) human genogroup II and animal genogroup I of F-specific RNA bacteriophages (FRNAPH) by culture/genotyping and by direct real-time reverse-transcriptase PCR. The higher occurrence of the human genogroup II of F-specific RNA bacteriophages using a culture/genotyping method, and human-associated Bacteroidales marker by real-time PCR, allowed the identification of human faecal contamination as the predominant source of contamination in oysters (total of 18 oyster batches tested) and waters (total of 24 water samples tested). The importance of using the intravalvular liquids instead of digestive tissues, when applying host-associated Bacteroidales markers in oysters, was also revealed. This study has shown that the application of a MST toolbox of diverse bacterial and viral methods can provide multiple lines of evidence to identify the predominant source of faecal contamination in shellfish from an estuarine environment. Application of this MST toolbox is a useful approach to understand the origin of faecal contamination in shellfish harvesting areas in an estuarine setting.

Pinnatoxin G is responsible for atypical toxicity in mussels (Mytilus galloprovincialis) and clams (Venerupis decussata) from Ingril, a French Mediterranean lagoon

Following a review of official control data on shellfish in France, Ingril Lagoon had been identified as a site where positive mouse bioassays for lipophilic toxins had been repeatedly observed. These unexplained mouse bioassays, also called atypical toxicity, coincided with an absence of regulated toxins and rapid death times in mice observed in the assay.The present study describes pinnatoxin G as the main compound responsible for the toxicity observed using the mouse bioassay for lipophilic toxins. Using a well-characterised standard for pinnatoxin G, LC-MS/MS analysis of mussel samples collected from 2009 to 2012 revealed regular occurrences of pinnatoxin G at levels sufficient to account for the toxicity in the mouse bioassays. Baseline levels of pinnatoxin G from May to October usually exceeded 40 μg kg−1 in whole flesh, with a maximum in September 2010 of around 1200 μg kg−1. These concentrations were much greater than those at the other 10 sites selected for vigilance testing, where concentrations did not exceed 10 μg kg−1 in a 3-month survey from April to July 2010, and where rapid mouse deaths were not typically observed. Mussels were always more contaminated than clams, confirming that mussel is a good sentinel species for pinnatoxins. Profiles in mussels and clams were similar, with the concentration of pinnatoxin A less than 2% that of pinnatoxin G, and pteriatoxins were only present in non-quantifiable traces. Esters of pinnatoxin G could not be detected by analysis of extracts before and after alkaline hydrolysis. Analysis with a receptor-binding assay showed that natural pinnatoxin G was similarly active on the nicotinic acetylcholine receptor as chemically synthesized pinnatoxin G. Culture of Vulcanodinium rugosum, previously isolated from Ingril lagoon, confirmed that this alga is a pinnatoxin G producer (4.7 pg cell−1). Absence of this organism from the water column during prolonged periods of shellfish contamination and the dominance of non-motile life stages of V. rugosum both suggest that further studies will be required to fully describe the ecology of this organism and the accumulation of pinnatoxins in shellfish.

High hydrostatic pressure activity on the disinfection of clams artificially contaminated with feline calicivirus.

The contamination of shellfish with gastroenteric viruses may cause outbreaks because they are often eaten raw or under-cooked. High-hydrostatic pressure treatments have already proven to be effective in reducing high viral load in shellfish samples. The objectives are the assessment of the viral load reduction of contaminated clams using HHP treatments at different pressures and times and the study of the changes caused by these treatments in some food physical parameters. Clams were contaminated with a solution containing Feline Calicivirus; they were closed in envelopes and treated with 300, 400, 500, 600 MPa for 1, 3, 5, 7 min for every pressure value. After the treatment the residual viral titre was calculated. The texture parameters were obtained after treating clams samples at the same pressure values but only for 3 and 7 min and analysing them with a TPA test. HHP treatments of 500 and 600 MPa were sufficient to cause a total inactivation at every timelength considered while with 300 and 400 MPa after 1 min, concentrations of 1.13 and 0.55 respectively were found. In general hardness and gumminess tend to increase after the treatment whereas springiness and cohesiveness decrease a bit. HHP treatments showed good sterilization ability against FCV but it's necessary to consider that FCV has a lower resistance to disinfection than Human norovirus. Texture changes are in line with what is reported in literature.

Prevalence of Human Enteric Viruses and a Potential Indicator of Contamination in Shellfish in China

AbstractThe objectives of this study were to quantify enteric viruses in shellfish along the Chinese coast and find an indicator of viral contamination in shellfish. One hundred sixty‐two samples were collected in August from 10 cities. Hepatitis A virus (HAV), norovirus (NV), rotavirus (RV), poliovirus (PV), astrovirus (AsV) and adenovirus (AdV) were detected by polymerase chain reaction (PCR) and confirmed by sequencing. The percentage of positive samples for each virus was as follows: HAV 5%, NV 12%, RV 7%, PV 15%, AsV 6% and AdV 9%. The six species of shellfish were contaminated with different viruses. PV showed a significant correlation with other viruses, with the exception of RV (P &lt; 0.05). Contamination of shellfish with human enteric viruses was common across a large geographical region of China, indicating a potential public health threat from seafood. The data confirm the potential to monitor the food safety of shellfish by using PV as an index of enteric virus contamination.Practical ApplicationsEnteric viruses are one of foodborne pathogens transmitted by bivalve shellfish, which pose a severe potential risk for consumers, as well as a serious problem facing researchers. China leads the worldwide production of shellfish. Therefore, the safety of shellfish harvested in China is particularly important. Norovirus, hepatitis A virus, rotavirus, adenovirus, poliovirus and astrovirus are introduced to assess the seafood safety by documenting risks for transmission of enteric viruses in shellfish along the Chinese coast. Of which, poliovirus could be one of these potential indicator to present human enteric virus contamination in the countries where oral polio vaccines are used.

Recent innovation in microbial source tracking using bacterial real-time PCR markers in shellfish

We assessed the capacity of real-time PCR markers to identify the origin of contamination in shellfish. Oyster, cockles or clams were either contaminated with fecal materials and host-associated markers designed from Bacteroidales or Catellicoccus marimammalium 16S RNA genes were extracted from their intravalvular liquid, digestive tissues or shellfish flesh. Extraction of bacterial DNA from the oyster intravalvular liquid with FastDNA spin kit for soil enabled the selected markers to be quantified in 100% of artificially contaminated samples, and the source of contamination to be identified in 13 out of 38 naturally contaminated batches from European Class B and Class C areas. However, this protocol did not enable the origin of the contamination to be identified in cockle or clam samples. Although results are promising for extracts from intravalvular liquid in oyster, it is unlikely that a single protocol could be the best across all bacterial markers and types of shellfish.

Norovirus and Other Human Enteric Viruses in Moroccan Shellfish

The aim of this study was to evaluate the presence of human enteric viruses in shellfish collected along the Mediterranean Sea and Atlantic Coast of Morocco. A total of 77 samples were collected from areas potentially contaminated by human sewage. Noroviruses were detected in 30 % of samples, with an equal representation of GI and GII strains, but were much more frequently found in cockles or clams than in oysters. The method used, including extraction efficiency controls, allowed the quantification of virus concentration. As in previous reports, results showed levels of contamination between 100 and 1,000 copies/g of digestive tissues. Sapoviruses were detected in 13 % of samples mainly in oyster and clam samples. Hepatitis A virus was detected in two samples, with concentrations around 100 RNA copies/g of digestive tissues. Only two samples were contaminated with enterovirus and none with norovirus GIV or Aichi virus. This study highlights the interest of studying shellfish samples from different countries and different production areas. A better knowledge of shellfish contamination helps us to understand virus levels in shellfish and to improve shellfish safety, thus protecting consumers.

Development and validation of an ultrasensitive fluorescence planar waveguide biosensor for the detection of paralytic shellfish toxins in marine algae

Marine dinoflagellates of the genera Alexandrium are well known producers of the potent neurotoxic paralytic shellfish toxins that can enter the food web and ultimately present a serious risk to public health in addition to causing huge economic losses. Direct coastal monitoring of Alexandrium spp. can provide early warning of potential shellfish contamination and risks to consumers and so a rapid, sensitive, portable and easy-to-use assay has been developed for this purpose using an innovative planar waveguide device. The disposable planar waveguide is comprised of a transparent substrate onto which an array of toxin–protein conjugates is deposited, assembled in a cartridge allowing the introduction of sample, and detection reagents. The competitive assay format uses a high affinity antibody to paralytic shellfish toxins with a detection signal generated via a fluorescently labelled secondary antibody. The waveguide cartridge is analysed by a simple reader device and results are displayed on a laptop computer. Assay speed has been optimised to enable measurement within 15min. A rapid, portable sample preparation technique was developed for Alexandrium spp. in seawater to ensure analysis was completed within a short period of time. The assay was validated and the LOD and CCβ were determined as 12pg/mL and 20pg/mL respectively with an intra-assay CV of 11.3% at the CCβ and an average recovery of 106%. The highly innovative assay was proven to accurately detect toxin presence in algae sampled from the US and European waters at an unprecedented cell density of 10cells/L.

Climate change impacts on natural toxins in food production systems, exemplified by deoxynivalenol in wheat and diarrhetic shellfish toxins

Climate change is expected to affect food and feed safety, including the occurrence of natural toxins in primary crop and seafood production; however, to date, quantitative estimates are scarce. This study aimed to estimate the impact of climate change effects on mycotoxin contamination of cereal grains cultivated in the terrestrial area of north west Europe, and on the frequency of harmful algal blooms and contamination of shellfish with marine biotoxins in the North Sea coastal zone. The study focused on contamination of wheat with deoxynivalenol, and on abundance of Dinophysis spp. and the possible relationship with diarrhetic shellfish toxins. The study used currently available data and models. Global and regional climate models were combined with models of crop phenology, mycotoxin prediction models, hydrodynamic models and ecological models, with the output of one model being used as input for the other. In addition, statistical data analyses using existing national datasets from the study area were performed to obtain information on the relationships between Dinophysis spp. cell counts and contamination of shellfish with diarrhetic shellfish toxins as well as on frequency of cereal cropping. In this paper, a summary of the study is presented, and overall conclusions and recommendations are given. Climate change projections for the years 2031–2050 were used as the starting point of the analyses relative to a preceding 20-year baseline period from which the climate change signal was calculated. Results showed that, in general, climate change effects lead to advanced flowering and harvest of wheat, and increased risk of contamination of wheat with deoxynivalenol. Blooms of dinoflagellates were estimated to occur more often. If the group of Dinophysis spp. behaves similarly to other flagellates in the future then frequency of harmful algal blooms of Dinophysis spp. may also increase, but consequences for contamination of shellfish with diarrhetic shellfish toxins are uncertain. Climate change will also have indirect effects on toxin contamination, which may be equally important. For example, the frequency of cropping of wheat and maize in north Europe was projected to increase under climate change, which will also increase the risk of contamination of the grains with deoxynivalenol. Risk managers are encouraged to consider the entire range of the predictions of climate change effects on food safety hazards, rather than median or average values only. Furthermore, it is recommended to closely monitor levels of mycotoxins and marine biotoxins in the future, in particular related to risky situations associated with favourable climatic conditions for toxin producing organisms. In particular, it is important to pay attention to the continuity of collecting the right data, and the availability and accessibility of databases. On a European level, it is important to stress the need for harmonisation of terminology and data collection.

Assessment of trace metal contamination in mangrove ecosystems from Senegal, West Africa

The inorganic contamination of sediment and harvested molluscs was investigated in the mangrove environment of Southern West Senegal. Trace metals were analysed in surface sediments, two bivalves (Arca senilis and Crassostera gasar) and three gastropods (Conus spp., Hexaplex duplex and Pugilina morio) collected from four stations: Dionewar, Niodor and Falia localised in the Saloum Delta, and Fadiouth from the Petite Côte. A geochemical normalisation approach by using aluminium allowed for discrimination of sediment contamination among sites. Indeed, Fadiouth appeared highly contaminated with Cd, Hg and Ni compared to the Saloum Delta. For all mangrove sites, trace metals exhibited significant higher concentrations (on a dry weight basis) in shellfish compared to sediments, excepted for Ni and Pb. The distribution pattern followed a similar global trend in molluscs regardless of the spatio-temporal variability, with the predominance of Zn (80% of total metals) followed by Cu and Cd. However, strong differences of metal bioavailability and bioaccumulation in biota were demonstrated, revealing the requirement of employing a suite of organism bioindicators to monitor metal contamination in mangrove ecosystems. From an ecotoxicological point of view, trace metal levels in sediments from the Petite Côte and the Sine-Saloum Estuary were below the effects range-low (ERL) threshold limit of the sediment quality guidelines for adverse biological effects (SQGs). On the opposite, some concerns about Cd contamination of edible shellfish from Southern West Senegal were highlighted, from both the safety point of view of local populations’ health, and the chemical quality point of view of exported resources.

Probabilistic dietary exposure to phycotoxins in a recreational shellfish harvester subpopulation (France)

Phycotoxins, secondary phytoplankton metabolites, are considered as an important food safety issue because their accumulation by shellfish may render them unfit for human consumption. However, the likely intakes of phycotoxins via shellfish consumption are almost unknown because both contamination and consumption data are very scarce. Thus, two 1-year surveys were conducted (through the same population: recreational shellfish harvesters and from the same geographical area) to assess: shellfish consumption and contamination by major toxins (domoic acid (DA) group, okadaic acid (OA) group and spirolides (SPXs)). Recreational shellfish harvesters had been targeted as an at-risk subpopulation because they consume more shellfish than general population and because they eat not only commercial shellfish species controlled by official authorities but also their own harvests of shellfish species may be in non-controlled areas and more over shellfish species non-considered in the official control species. Then, these two kinds of data were combined with deterministic and probabilistic approaches for both acute and chronic exposures, on considering the impact of shellfish species and cooking on phycotoxin levels. For acute risk, monitoring programs seem to be adequate for DAs, whereas OAs could be a matter of concern for high consumers (their acute intakes were up to ninefold the acute reference dose (ARfD)). About chronic risk, OAs are a matter of concern. The daily OAs intakes were close to the ARfD, which is, by definition, greater than the tolerable daily intake. Moreover, SPX contamination is low but regular, no (sub)chronic SPX toxicity data exist; but in case of (sub)chronic toxicity, SPX exposure should be considered.

Two-Year Systematic Study To Assess Norovirus Contamination in Oysters from Commercial Harvesting Areas in the United Kingdom

The contamination of bivalve shellfish with norovirus from human fecal sources is recognized as an important human health risk. Standardized quantitative methods for the detection of norovirus in molluscan shellfish are now available, and viral standards are being considered in the European Union and internationally. This 2-year systematic study aimed to investigate the impact of the application of these methods to the monitoring of norovirus contamination in oyster production areas in the United Kingdom. Twenty-four monthly samples of oysters from 39 United Kingdom production areas, chosen to represent a range of potential contamination risk, were tested for norovirus genogroups I and II by using a quantitative real-time reverse transcription (RT)-PCR method. Norovirus was detected in 76.2% (643/844) of samples, with all sites returning at least one positive result. Both prevalences (presence or absence) and norovirus levels varied markedly between sites. However, overall, a marked winter seasonality of contamination by both prevalence and quantity was observed. Correlations were found between norovirus contamination and potential risk indicators, including harvesting area classifications, Escherichia coli scores, and environmental temperatures. A predictive risk score for norovirus contamination was developed by using a combination of these factors. In summary, this study, the largest of its type undertaken to date, provides a systematic analysis of norovirus contamination in commercial oyster production areas in the United Kingdom. The data should assist risk managers to develop control strategies to reduce the risk of human illness resulting from norovirus contamination of bivalve molluscs.