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Simple Summary: Microplastics (MPs) are anthropogenic microscopic pieces of plastic in marine sediments and the water column that can originate from two different sources. Primary MPs are industrially produced microbeads, while secondary MPs result from the fragmentation of larger plastic debris by physical, chemical, and biological processes. Although not yet considered a food contaminant, they are readily ingested by marine organisms at several trophic levels, thus entering the food chain and representing a risk to consumers of fishery products. In this study, Donax trunculus (Truncate donax) specimens collected from Class A production areas in the Tyrrhenian Sea (Mediterranean Sea), and therefore destined directly for the final consumer, were analyzed for the presence of MPs. First, all items were morphologically classified and measured, and some of these were chemically identified. Then, the MPs' mean abundance (MA) was calculated, and a risk assessment of human exposure to MPs was carried out. Both the MA of MPs and human exposure to MPs were found to be low. However, given the magnitude of the problem, the collection of further data using standardized methods is essential for a better risk assessment. Microplastics (MPs) (0.1 µm–5 mm particles) have been documented in oceans and seas. Bivalve molluscs (BMs) can accumulate MPs and transfer to humans through the food chain. BMs (especially mussels) are used to assess MPs' contamination, but the genus Donax has not been thoroughly investigated. The aim of this study was to detect and characterize MPs in D. trunculus specimens collected along the Tuscan coast (Italy), and to assess the potential risk for consumers. The samples (~10 g of tissue and intervalval liquid from 35 specimens) were digested using a solution of 10% KOH, subjected to NaCl density separation, and filtered through 5 μm pore-size filters. All items were morphologically classified and measured, and their mean abundance (MA) was calculated. Furthermore, 20% of them were analyzed by Raman spectroscopy and, based on the obtained results, the MA was recalculated (corrected MA) and the annual human exposure was estimated. In the 39 samples analyzed, 85 items fibers (n = 45; 52.94%) and fragments (n = 40; 47.06%) were found. The MA was 0.23 ± 0.17 items/grww. Additionally, 83.33% of the items were confirmed as MPs (polyethylene and polyethylene terephthalate). Based on the correct MA (0.18 MPs/grww), D. trunculus consumers could be exposed to 19.2 MPs/per capita/year. The health risk level of MPs was classified as level III (moderate). [ABSTRACT FROM AUTHOR]

Concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were investigated in six species of bivalve mollusc purchased on the Polish retail market. The risk to consumers was calculated as a percentage of the tolerable weekly intake (TWI) (2 pg World Health Organization toxic equivalent (WHO-TEQ) kg−1 body weight (b.w.)). Altogether 32 samples were analysed using an isotope dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry. Low levels of all analysed compounds were found. The range of PCDD/Fs was 0.08–0.37 pg WHO-TEQ g−1 of wet weight (w.w.) and 0.04–0.41 pg WHO-TEQ g−1 w.w. for DL-PCBs. The highest concentrations of all analysed compounds were found in Pacific oysters, at 0.30 pg WHO-TEQ g−1 w.w. for the sum of PCDD/Fs and 0.19 pg WHO-TEQ g−1 for the sum of DL-PCBs. These concentrations were 2–4 times higher than those detected in the other analysed mollusc species. Different species-dependent congener profiles were observed for PCDD/F concentrations, while PCB congener concentration profiles were species independent. The risk to consumers was assessed relating theoretical intakes of PCDD/Fs and DL-PCBs per 25, 50 and 100 g of consumption of molluscs per week to the TWI. Taking into account the low consumption of molluscs in Poland and low concentrations of analysed compounds, neither adults nor children are likely to exceed the TWI by ingestion of food in this category. [ABSTRACT FROM AUTHOR]

Twelve trace elements were studied in four economically important bivalve molluscs (Mediterranean mussel, manila clam, striped venus clam, and truncated wedge clam) from the southern Marmara Sea for seasonal bioaccumulation and human health risk assessment. According to the findings, Fe and Zn were the most accumulative and element concentrations changed considerably (P < 0.05) between seasons and species. Daily, weekly, monthly intake and target hazard quotients of the trace elements were estimated and compared with maximum limits. The results revealed that consuming these bivalve molluscs from the southern Marmara Sea could be considered safe for human consumption. Nevertheless, further monitoring is needed in order to better follow the development in time of elemental pollution due to increasing environmental pressure on the Marmara Sea basin, together with research on other different bioaccumulative organisms. [ABSTRACT FROM AUTHOR]

This work describes a method for the determination of paralytic shellfish toxins in mussels (M. galloprovincialis) , oysters (Crassostrea gigas), and clams (Ruditapes decussatus) samples. The acetic acid extraction method is used for simultaneous analysis of Paralytic Shellfish Poisoning (PSP) and the separation of these compounds was achieved on ethylene bridged hybrid (BEH) Amide column with gradient mobile phase composed of acetonitrile (MeCN) and water (as eluent A and eluent B) both containing 2 mM ammonium formate and 50 mM formic acid. The method specificity, linearity, sensitivity, precision, and accuracy were successfully evaluated towards the detection of 13 hydrophilic marine biotoxins analyzed together (single run) in different sample matrixes such as mussels. oysters. and clams. Calibration curves were found to be linear (R2 ≥ 0.98). average Recovery% of 98.5–99.9%. limits of detection (LODs): 0.16–1.92 µg·kg−1; limits of quantitation (LOQs): 0.54–6.41 µg·kg−1) and the relative standard deviation (RSD%) of the precision was ≤ 2.8%. The method was applied for the determination of PSP in shellfish collected from several Tunisian locations. All LC-MS/MS results of analyzed molluscs collected from different Tunisia locations, reveal no PSP toxin group contamination and that the amount found does not exceeding the threshold of 800 µg STXequ·kg−1. [Display omitted] • A proposed official alternative method of analysis for regulatory control and food safety. • Simultaneous determination of paralytic shellfish toxins using LC-MSMS. • A highly sensitive detection of shellfish biotoxins. • Validation of the method for paralytic shellfish toxins determination. • Effectiveness of proficiency testing within 34 different laboratories. [ABSTRACT FROM AUTHOR]

We examined the occurrence and levels of 19 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in 7 species of marine bivalve molluscs collected from four coastal cities of Shandong Province, China. Perfluorooctanoic acid (PFOA) was the most prevalent component, accounting for 68.1 % of total PFASs. The total PFASs in bivalve molluscs ranged from 0.86 to 6.55 ng/g wet weight, with the highest concentration found in Meretrix meretrix L. The concentration of total PFASs in bivalve molluscs showed the following trend: clams > scallops > oysters > mussels. Estimation on the human intake of PFASs from consumption of bivalve molluscs resulted in hazard ratios (HR) ranging from 0.12 to 6.40. Five of the seven species had HR >1, indicating high exposure risks associated with PFASs. Therefore, the occurrence of PFASs in marine biota is particularly concerning and further investigations on the sources of PFASs in Shandong are warranted. • First time detection of 19 PFASs in bivalve molluscs in Shandong Province • PFASs levels in bivalve molluscs varied from 0.86 to 6.55 ng/g wet weight. • PFOA, PFBA, PFNA and PFOS were the compounds most frequently detected. • Frequent consumption of bivalve molluscs may pose health risk. [ABSTRACT FROM AUTHOR]

Marine biotoxins are toxic substances that may cause illness and death in marine organisms and humans. This article disseminates the results of a 4-year study on the occurrence of marine biotoxins in raw bivalve molluscs purchased from Polish suppliers. A total of 256 samples of 8 different molluscs species were analysed for the presence of biotoxins using the ELISA method for paralytic shellfish poison, diarrhoetic shellfish poison, and amnaesic shellfish poison. The permitted limits of marine biotoxin content were not exceeded in any of the analysed samples and the majority of them were free from these compounds. The results of the study indicate that the tested raw bivalve molluscs available in Poland were safe for consumers. [ABSTRACT FROM AUTHOR]

Human noroviruses are recognized as the leading worldwide cause of sporadic and epidemic viral gastroenteritis, causing morbidity and mortality in impoverished developing countries and engendering enormous economic losses in developed countries. Transmitted faecal‐orally, either via person‐to‐person contact, or by consumption of contaminated foods or water, norovirus outbreaks are often reported in institutional settings or in the context of communal dining. Bivalve molluscs, which accumulate noroviruses via filter feeding and are often eaten raw or insufficiently cooked, are a common food vehicle implicated in gastroenteritis outbreaks. The involvement of bivalve molluscs in norovirus outbreaks and epidemiology over the past two decades are reviewed. The authors describe how their physiology of filter feeding can render them concentrated vehicles of norovirus contamination in polluted environments and how high viral loads persist in molluscs even after application of depuration practices and typical food preparation steps. The global prevalence of noroviruses in bivalve molluscs as detected by different monitoring efforts is determined and the various methods currently utilized for norovirus extraction and detection from bivalve matrices described. An overview of gastroenteritis outbreaks affirmatively associated with norovirus‐contaminated bivalve molluscs as reported in the past 18 years is also provided. Strategies for risk reduction in shellfish contamination and subsequent human infection are discussed. [ABSTRACT FROM AUTHOR]

In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was originally developed for simultaneously quantitative analysis of twelve paralytic shellfish poisoning toxins, referring to STX, NEO, dcSTX, GTX1, GTX2, GTX3, GTX4, GTX5, C1, C2, dcGTX2, and dcGTX3 in bivalve molluscs. Chromatographic separations were performed on a TSK-Gel Amide-80 column (5 μm, 2.0 × 150 mm, Tosoh Corporation) by gradient elution with 2 mmol L−1 ammonium formate solution-acetonitrile (containing 0.1% formic acid) as mobile phases. The samples were pretreated by extraction with acetonitrile-water (80:20, v/v; containing 0.1% formic acid), followed by cleaning up using an Oasis HLB extraction cartridge (500 mg/6 mL). The present method showed good linearity (r2 > 0.99) with the limits of detection (LODs) and limits of quantification (LOQs) ranged from 1.03 to 10.65 μg/kg and 3.43–35.46 μg/kg, respectively for these toxins. Owing to its sensitivity and rapid properties, the presented method was applied to the determination of PSP toxins in bivalve molluscs involved in a food poisoning incident occurred in Zhangzhou, China, in June 2017. • New ultra-performance liquid chromatography-tandem mass spectrometry method. • Simultaneously quantitative analysis of twelve paralytic shellfish poisoning toxins. • Determine of the toxins in bivalve molluscs involved in a food poisoning incident. • The method is sensitive and rapid in comparison to previous ones. [ABSTRACT FROM AUTHOR]

Bivalve molluscs possess effective cellular and humoral defence mechanisms against bacterial infection. Although the immune responses of mussels to challenge with pathogenic vibrios have been largely investigated, the effects at the site of injection at the tissue level have not been so far evaluated. To this aim, mussels Mytilus galloprovincialis were herein in vivo challenged with Vibrio splendidus to assess the responses induced in hemolymph and posterior adductor muscle (PAM), being the site of bacterial infection. The number of living intra-hemocyte bacteria increased after the first hour post-injection (p.i.), suggesting the occurrence of an intense phagocytosis, while clearance was observed within 24 h p.i. A recruitment of hemocytes at the injection site was found in mussel PAM, together with marked morphological changes in the volume of muscular fibers, with a recovery of muscle tissue organization after 48 h p.i. A concomitant impairment in the osmoregulatory processes were observed in PAM by an initial inhibition of aquaporins and increased immunopositivity of Na+/K+ ATPase ionic pump, strictly related to the histological alterations and hemocyte infiltration detected in PAM. Accordingly, an intense cell turnover activity was also recorded following the infection event. Overall, results indicated the hemolymph as the system responsible for the physiological adaptations in mussels to stressful factors, such as pathogenicity, for the maintenance of homeostasis and immune defence. Also, the osmotic balance and cell turnover can be used as objective diagnostic criteria to evaluate the physiological state of mussels following bacterial infection, which may be relevant in aquaculture and biomonitoring studies. Unlabelled Image • Mussels Mytilus galloprovincialis were in vivo challenged with Vibrio splendidus. • The number of living intra-hemocyte bacteria increased after 1 h post-infection. • Histological changes and recruitment of hemocytes occurred at the injection site. • Impairment of osmoregulation and cell turnover activity were found in mussel muscles. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Natural radionuclides and 137Cs in different types of bivalve molluscs were determined by alpha and gamma spectrometry. • 137Cs was below the minimum detectable activity concentration in all bivalves samples. • The annual ingestion doses due to bivalves ingestion were assessed. • A statistical analysis of natural radioactivity was used to discriminate between molluscs of Atlantic and Mediterranean. Abstract The presence of natural and artificial radionuclides in the marine environment produces the accumulation of radionuclides in bivalve molluscs consumed by humans, and therefore it could result in a radiological hazard. In this study, the activity concentrations of 210Po, 40K, 210Pb and 234Th were determined in different types of bivalve molluscs sampled during the period of May 2014–June 2015, along coastal areas from the Andalusian region (South of Spain), through alpha-particle spectrometry and low-level gamma-ray spectrometry. The activity concentrations of 210Po; 40K; 210Pb and 234Th varied between 40 ± 2 and 515 ± 9 Bq kg−1 dry weight (d.w.); 121 ± 7 and 674 ± 34 Bq kg−1 d.w.; ND (lower than limit of detection) and 73 ± 10 Bq kg−1 d.w.; and ND and 126 ± 27 Bq kg−1 d.w., respectively. The committed effective dose to humans was calculated to range from 41 to 479 μSv year−1. Both activity concentrations and dose levels were comparable to previous studies from other countries. Finally, a multivariate statistical analysis of natural radioactivity content allowed the discrimination between bivalve molluscs from Atlantic and Mediterranean coasts. [ABSTRACT FROM AUTHOR]

Abstract Worldwide bivalve production has increased significantly in recent years. Bivalve meat is recommended in dietary regimens due to the benefits associated with their consumption but, at the same time, is internationally recognized as a potential vehicle for outbreaks of foodborne disease. To reduce food risk exposure, consumers must pay close attention when purchasing, handling and consuming bivalves. This study aimed to collect information on consumers' perceptions and practices related to bivalve purchasing, managing and consumption at home. A focus group methodology was adopted to better understand consumers' food practices and risk perceptions regarding molluscs. Four focus groups involving 42 consumers were conducted in Veneto and Marche region. The core analysis was then applied to each focus group discussion in order to identify, categorize and rank the information collected. The most important factors that came to light during the focus groups concerned the personal reasons for preparing bivalves at home; the place of purchase; the elements guiding consumers when purchasing bivalves; the bivalve preparation, cooking and storage conditions at home; the consumption of raw molluscs and the health risks; the consumers' categories most at risk; and the production chain control by the authorities. The data reported in the article can provide useful information to public authorities working on food safety for developing effective risk communication strategies. Highlights • Consumers play a crucial role in food risk reduction. • The focus group methodology collected information from Italian consumers. • The study analysed consumers' purchasing, handling and consumption of bivalves. • The data provide useful information for implementing risk communication activities. [ABSTRACT FROM AUTHOR]

Highlights • Bivalve molluscs species were analyzed by ICP OES and ICP-MS. • Most Lucina pectinata samples had higher concentrations of Cu, Cr and Pb. • Concentrations of As obtained in most samples were above the legal limit recommended by ANVISA. • PCA and HCA showed separation between Lucina pectinata and Trachycardium muricatum species. Abstract Four species of bivalve molluscs (Anomalocardia brasiliana , Iphigenia brasiliana , Lucina pectinata and Trachycardium muricatum) were collected in the Todos os Santos Bay (TSB), Bahia, Brazil, in order to evaluate As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, V and Zn levels and, consequently, the risk of bivalve mollusc consumption in humans. The samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) after closed-vessel microwave digestion. The accuracy was confirmed using the certified reference materials of oyster tissue (NIST 1566b) and mussel tissue (NIST 2977), and the results were statistically equivalent to the certified values. Application of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a tendency to form two groups between samples of Lucina pectinata and Trachycardium muricatum. All species showed As and Cr concentrations higher than the maximum tolerable limit specified in Brazilian legislation. [ABSTRACT FROM AUTHOR]

Norovirus (NoV) and Hepatitis A virus (HAV) are the most important viral hazards associated with human illness following consumption of contaminated bivalve molluscs. The effectiveness of the current EU criteria for heat processing of bivalve molluscs (i.e. raising the temperature of the internal mollusc flesh to at least 90°C for a minimum of 90 seconds) was evaluated using predictive microbiology. A HAV thermal inactivation model was developed based on literature data in mollusc matrices during isothermal heat treatment. Application of the developed model demonstrated that the 90°C-90 s requirement may lead to significantly different virus inactivation depending on the commercial process design. This shows the need for the establishment of a Performance Criterion for bivalve molluscs heat processing which will assure a common specified level of consumer protection. A risk-based approach is described that allows for an effective processing design providing a more transparent and objective relation between the thermal processing targets and public health. Model simulations demonstrate that the F-value is a more appropriate Process Criterion than a single time-temperature combination since it enables the food business operators to design a process that is compliant with the safety requirements while at the same time achieving a desired product quality. [ABSTRACT FROM AUTHOR]

In this study, the activity concentrations of 210 Po and 210 Pb were determined in different types of bivalve molluscs sampled during the period of May 2014–June 2015 along the Andalusian littoral. Radioactivity concentrations of 210 Po were determined through alpha-particle spectrometry using 209 Po as an internal tracer. Radioactivity concentrations of 210 Pb were determined through low-level gamma-ray spectrometry. The activity concentrations of 210 Po and 210 Pb varied between 40 ± 2 and 515 ± 9 Bq kg −1  dry weight (d.w.), and ND (lower than limit of detection) and 73 ± 10 Bq kg −1  d.w., respectively. The committed effective dose to humans was calculated to range from 39 to 477 μSv year −1 . Radioactivity and dose levels were compared with previous studies from other countries. [ABSTRACT FROM AUTHOR]

Bivalve molluscs, including oysters and scallops, are hedonic foods that have been a valuable source of vitamins, minerals and proteins in the human diet since the Stone Age. Despite being rich in beneficial compounds, it is still debatable whether bivalves should be regarded as a healthy food since they can accumulate harmful microorganisms, and toxic compounds from the surrounding environment. Currently, there is still no in-depth understanding of the ultimate effect of bivalve consumption on humans. The use of advanced foodomics approaches is beginning to provide a more detailed characterisation of the beneficial and deleterious compounds in these seafood products. In addition to defining bivalve molluscs within an international dietary framework, this review highlights the major nutritional components of their metabolome (foodome) with a focus on several groups of toxicants whose presence can negatively offset their nutritional value. An overview of metabolomics applications to the study of bivalve molluscs is included. [ABSTRACT FROM AUTHOR]

Aims The aim of this study was to detect and quantify Aichi virus (AiV) in shellfish from three estuaries in Galicia, the main producer of molluscs in Europe. Methods and Results A total of 249 shellfish samples were analysed using a reverse transcription-quantitative PCR procedure. AiV was detected in 15 of 249 (6·02%) samples. Ría de Ares-Betanzos showed the highest prevalence (11·1%), followed by Ría do Burgo (3·7%) and Ría de Vigo, (2·56%). AiV quantifications ranged from nonquantifiable (under the limit of quantification of the method) to 6·9 × 103 RNAc per g DT, with a mean value of 1·9 × 102 RNAc per g DT. Conclusion Results obtained indicated that the prevalence of this enteric virus in the studied area is considerably lower than those of other enteric viruses, such as Norovirus, Sapovirus, HAV or HEV. Significance and Impact of the Study This is the first study that detects the presence of AiV in shellfish from authorized harvesting areas in Spain. Further studies with clinical samples are needed to determine the potential risk of AiV for human health in Galicia. [ABSTRACT FROM AUTHOR]

Considering that several recent cases of human gastroenteritis have been associated with species from the Arcobacter genus, and that few data are currently available about the occurrence of this genus in Italian shellfish, the aim of the present study was to evaluate the occurrence of Arcobacter spp. and the presence of virulence-associated genes. The approach consisted of cultural and biomolecular (multiplex-PCR and 16S-RFLP) methods identifying isolates, followed by PCR assays aimed at the cadF , ciaB , cjl349 , irgA , hecA putative virulence genes. Arcobacter spp. was detected in 16/70 (22.8%) shellfish samples. Specifically, Arcobacter spp. was highlighted in 10/42 (23.8%) mussel and in 6/28 (21.4%) clam samples. Subsequently, biomolecular assays revealed Arcobacter butzleri in 12/16 (75%) and Arcobacter cryaerophilus 1B in 4/16 (25%) isolates. PCRs aimed at the five putative virulence genes demonstrated widespread distribution of these genes among Arcobacter isolates and some differences from the results published by other authors. Our research provides more information regarding the health risks associated with the consumption of raw bivalve molluscs and underlines the need to implement an adequate control plan by performing intensive and continuous monitoring in order to guarantee human health. [ABSTRACT FROM AUTHOR]

A total of 85 mussel samples of eight species were examined. Analysis of mercury in the freeze-dried samples was carried out by atomic absorption spectrometry method using direct mercury analyser AMA 254. The analytical procedure for determination of mercury was covered by the quality assurance programme of research and participation in national and international proficiency tests. Concentrations of total mercury in all investigated samples were found to be generally low, in the range of 0.033-0.577 mg/kg of dry weight and of 0.003-0.045 mg/kg of wet weight. The results indicate that obtained levels of mercury in bivalve molluscs are not likely to pose a risk to the health of consumers. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the prevalence and antibiogram of Vibrio parahaemolyticus in processed bivalve molluscs in Kuala Terengganu. A total of 80 seafood samples, namely mussels (n=20), carpet clams (n=20), cockles (n=20) and scallops (n=20), were subjected to PCR and conventional plating method for the detection of V. parahaemolyticus. V. parahaemolyticus was found in green mussels (55%), carpet clam (80%), cockles (40%) and scallops (55%). Fifty- five V. parahaemolyticus isolates were subjected to 9 types antibiotic sensitivity test using discs diffusion method. All isolates were susceptible to Tetracycline and Gentamycin. Isolates showed high resistance towards Vancomycin (52.73%), Penicillin (45.45%) and Amplicillin (32.73%). Resistance towards Amikacin, Ciprofloxacin and Norfloxacin were found to be 1.82%. It can be concluded that local bivalve molluscs were contaminated with V. parahaemolyticus and isolates showed resistance towards certain antibiotics. Therefore, consumption of raw or semi-cooked bivalve molluscs is not advisable. [ABSTRACT FROM AUTHOR]

Materials are summarized on reaction of enzymatic antioxidant (AO) complex of tissues molluscs of the genus Mytilus on oxidative load of different intensity. It is shown that with increase of the level of oxidative stress there is observed a rise of activities of glutathione reductase (GR) and glutathione peroxidase (GP) as well as increases the turnover rate of glutathione (GSH) in tissues. Then the toxic load is compensated by an elevation of activities of enzymes of low affinity to hydroperoxides, specifically of catalase. In the glutathione system it is possible to identify several relatively steady states: processes of low, moderate, and high intensity. In individual tissues, functioning of the AO system seems to be directed not to detoxication, but to generation of reactive oxygen species (O, superoxide dismutase), which probably is determined by specifics of their running processes (destruction of damaged byssus threads). The AO complex of molluscs is distinguished by high lability and sensitivity both to physiological states (spanning) and to action of factors of anthropogenic nature (cationic detergents). Responses of the mussel AO complex to natural states and toxic action are comparable between each other, which are necessary to be taken into account at diagnostics of the state of the aquatic environment. [ABSTRACT FROM AUTHOR]

Abstract: Marine biotoxins synthesized by Harmful Algal Blooms (HABs) represent one of the most important sources of contamination in marine environments as well as a serious threat to fisheries and aquaculture-based industries in coastal areas. Among these biotoxins Okadaic Acid (OA) is of critical interest as it represents the most predominant Diarrhetic Shellfish Poisoning biotoxin in the European coasts. Furthermore, OA is a potent tumor promoter with aneugenic and clastogenic effects on the hereditary material, most notably DNA breaks and alterations in DNA repair mechanisms. Therefore, a great effort has been devoted to the biomonitoring of OA in the marine environment during the last two decades, mainly based on physicochemical and physiological parameters using mussels as sentinel organisms. However, the molecular genotoxic effects of this biotoxin make chromatin structure a good candidate for an alternative strategy for toxicity assessment with faster and more sensitive evaluation. To date, the development of chromatin-based studies to this purpose has been hampered by the complete lack of information on chromatin of invertebrate marine organisms, especially in bivalve molluscs. Our preliminary results have revealed the presence of histone variants involved in DNA repair and chromatin specialization in mussels and clams. In this work we use this information to put forward a proposal focused on the development of chromatin-based tests for OA genotoxicity in the marine environment. The implementation of such tests in natural populations has the potential to provide an important leap in the biomonitoring of this biotoxin. The outcome of such monitoring may have critical implications for the evaluation of DNA damage in these marine organisms. They will provide as well important tools for the optimization of their harvesting and for the elaboration of additional tests designed to evaluate the safety of their consumption and potential implications for consumer''s health. [Copyright &y& Elsevier]

Abstract: PCR protocols directly applied to enrichment broth cultures were compared with a culture method based on the ISO reference for detection of Vibrio parahaemolyticus in 57 natural bivalve mollusc samples. Comparisons were made on different primer pairs specifically targeting the V. parahaemolyticus-specific toxR gene (Vp-toxR) and pR72H fragment, and also tdh and trh hemolysin genes. The PCR method using these different primer pairs and the culture method were also examined for their limits of detection (LOD). The LODs ranged from 7–24 pg of purified DNA per reaction tube (RT) for primer pair Vp-toxR, but for primer pair pR72H, varied greatly depending on the V. parahaemolyticus strains used (0.7 pg–10.6 ng/RT). The Vp-toxR and pR72H primers allowed the detection of V. parahaemolyticus in 25 and 8 out of the 57 samples, respectively, while only 3 V. parahaemolyticus-positive samples were obtained by the culture method. The effective presence of V. parahaemolyticus in the Vp-toxR-positive samples was confirmed by sequencing the PCR products. The trh and Vp-toxR genes were simultaneously detected in 14% of the samples, which were thus considered as presumptively contaminated with pathogenic V. parahaemolyticus. These results emphasize the need for an efficient survey of both the total and pathogenic V. parahaemolyticus present in seafood in France. The PCR protocol targeting Vp-toxR followed by tdh and trh genes is an efficient and reliable method for the detection of total and presumptively pathogenic V. parahaemolyticus in bivalve molluscs. [Copyright &y& Elsevier]

The article presents a study on the estradiol-17ß and testosterone levels in the cockle Fulvia mutica during the annual reproductive cycle in China. The study underwent investigation on seasonal variations in the concentrations of estradiol-17ß and testosterone in the gonad of the cockle Fulvia mutica from March 2004 to February 2005 relative to the reproductive cycle. Histological data revealed that Fulvia mutica is a hermaphrodite bivalve specie and development and maturation of sex cells took place during winter and spring and spawning happened in summer when water temperature was higher.

In this work data of salinity, temperature, suspended particulate matter (SPM), chlorophyll-a, and phytoplankton concentration in the Gibraltar Strait coast, in the confluence of the Mediterranean Sean and the Atlantic Ocean, were analyzed together with 210Po, 40K, 210Pb and 234Th activity concentration in different types of bivalve molluscs at the same time-period. The physicochemical parameters were evaluated using the Copernicus Marine Environment Monitoring Service (CMEMS) products based on satellite observations. A multivariate statistical analysis, including contrasted natural radioactivity contents, allowed the discrimination of bivalve molluscs from Atlantic and Mediterranean coasts. Additionally, a cluster analysis determined a highly significant negative correlation 210Po concentration in molluscs and phytoplankton concentration suggesting that phytoplankton concentration in the water column is a determinant factor to regulate 210Po concentration in those animals. These results introduce a useful tool to calculate the radiological doses in seafood from chlorophyll satellite image. • First time that physicochemical parameters based on satellite observations were analyzed with activity concentration. • A significant negative correlation was shown between 210Po concentration in molluscs and phytoplankton concentration. • A multivariate statistical analysis allowed the discrimination of bivalve molluscs from Atlantic and Mediterranean coasts. • Radiological doses in seafood were obtained through chlorophyll satellite image. [ABSTRACT FROM AUTHOR]

Abstract: In the framework of the national monitoring program for marine biotoxins in bivalve molluscs for 2002 and 2003, a total of 862 samples were examined to investigate the presence of domoic acid (DA). Samples mainly consisted of mussels (Mytilus galloprovincialis) and venus clams (Venus verucosa) from various Greek harvesting areas. In 2002, 83% of all samples examined contained less that 1μg DA/g, while in 2003 this percentage was 95%. In both years, DA was only detected in springtime without any sample exceeding the regulatory level. In 2002, the highest value was 14.0μg/g in mussels, while in 2003 these were 4.2μg/g in mussels and 5.6μg/g in venus clams. This is the first report regarding the presence of ASP toxins in Greek shellfish. [Copyright &y& Elsevier]

The current study presents data on the antimicrobial resistance (AMR) patterns of 102 S. enterica subsp. enterica (72 Salmonella ser. Typhimurium and 30 monophasic S. Typhimurium serovar) and 79 Escherichia coli (and their phylogenetic group determination) isolates from different species of bivalve molluscs and from the water samples collected from the sub-areas of a mollusc production area near Ferrara (Italy). These areas were classified as Long-line, Lupini, B-Out, B-in, and Sacca. A retrospective evaluation was performed to assess the spatial trends of the resistance patterns of Salmonella and E. coli and the temporal trend for Salmonella ; the role of molluscs as AMR indicators and the potential use of E. coli as a microorganism indicator of AMR occurrence in a seawater environment were also investigated. Overall, 81% of Salmonella spp. and 75% of E. coli isolates were resistant to, at least, one antimicrobial agent (AA) and 44% and 38% of the isolates were multidrug resistant (MDR), respectively. The resistance levels of Salmonella were influenced by the investigated serovars. Monophasic S. Typhimurium serovar showed the highest resistance value with 70% of MDR isolates, in contrast with only 33% in S. Typhimurium. In monophasic S. Typhimurium versus S. Typhimurium, twofold resistance levels were observed to streptomycin (97 versus 43%), ampicillin (80 versus 40%) and tetracyclines (67 versus 36%). Regarding the temporal trend for Salmonella , strains were resistant to, at least, one AA, but this resistance was significantly lower during the first years of this 17-year sampling; however, in parallel MDR isolates, the resistance increased from 23% to a maximum level of 57% during the 2008–2012 period. On assessing the spatial trends, the Sacca area was found to show the lowest number of Salmonella spp. and E. coli strains resistant to, at least, one AA and MDR. For E. coli , the most commonly observed resistance was towards ampicillin (56%), streptomycin (52%), sulphonamides (30%) and ceftiofur (24%). The great majority (65%) of E. coli isolates belonged to the commensal phylogroups A and B1, with B1 as the dominant one, whereas most MDR isolates belonged to phylogroup C. Molluscs may be an efficient tool for antimicrobial resistance monitoring, and E. coli could be used as a microorganism indicator of the occurrence of antimicrobial resistance in seawater environment. • Bivalve molluscs are confirmed as efficient tool for antimicrobial resistance monitoring. • High multi-resistant levels were observed in Salmonella spp. and E. coli from molluscs and water. • Resistance levels for Salmonella are influenced by the investigated serovars. • Spatial trends of MDR Salmonella strains are observed. [ABSTRACT FROM AUTHOR]

• Mytilitol was unambiguously identified in M. edulis and R. philippinarum. • A new method for the synthesis of mytilitol was described. • A species-specific distribution of mytilitol in the samples was evidenced. • A geographical-dependent distribution of mytilitol in the samples was evidenced. This study presents a level-1 identification of the seven carbon (7-C) sugar C-methyl-scyllo-inositol (mytilitol) in mussels and clams (Mytilus and Ruditapes spp., respectively) purchased in Denmark and Italy. For each sample, the hydrophilic extract of the soft tissue was analyzed by proton nuclear magnetic resonance (1H NMR) spectroscopy using a 600 MHz NMR spectrometer. A first tentative identification of mytilitol was carried out by computing a statistical total correlation spectroscopy (STOCY) analysis of the 1H NMR spectra, followed by a level-1 identification based on first-principles methods including chemical synthesis, structure elucidation and standard-addition experiments. Mytilitol was quantified in the 1H NMR spectra and its average relative concentration turned out to be significantly lower in clams than in mussels (p-value < 0.001), with Danish mussels having the highest mytilitol concentration. Principal component analysis (PCA) of the NMR dataset brought further evidence to a species-specific and geographic-dependent content of mytilitol in mussels and clams. [ABSTRACT FROM AUTHOR]

In 2015, tetrodotoxins (TTXs) were considered a potential threat in Europe since several studies had shown the presence of these toxins in European bivalve molluscs. In this study, we investigated the occurrence of TTXs in 127 bivalve samples (mussels and oysters) and in 66 gastropod samples (whelks) collected all along the French mainland coasts in 2017 and 2018. Analyses were carried out after optimization and in-house validation of a performing hydrophilic interaction liquid chromatography associated with tandem mass spectrometry (HILIC-MS/MS) method. The concentration set by European Food Safety Authority (EFSA) not expected to result in adverse effects (44 µg TTX equivalent/kg) was never exceeded, but TTX was detected in three mussel samples and one whelk sample (1.7–11.2 µg/kg). The tissue distribution of TTX in this whelk sample showed higher concentrations in the digestive gland, stomach and gonads (7.4 µg TTX/kg) than in the rest of the whelk tissues (below the limit of detection of 1.7 µg TTX/kg). This is the first study to report the detection of TTX in French molluscs. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX) and its analogues are naturally occurring toxins responsible worldwide for human intoxication cases and fatalities, mainly associated with pufferfish consumption. In the last decade, TTXs were detected in marine bivalves and gastropods from European waters. As TTXs are not regulated or monitored at EU level, their unexpected occurrence in shellfish raised concerns as a food safety hazard and revealed the necessity of a thorough assessment on the public health risks associated with their presence. For this reason, the European Food Safety Authority (EFSA) was requested by the European Commission to provide a scientific opinion, finally adopted in March 2017, according to which a provisional concentration below 44 μg TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, was considered not to result in adverse effects in humans. The EFSA expert panel, however, recognized a number of shortcomings and uncertainties related to the unavailability of sufficient scientific data and provided relevant recommendations for future research to overcome these data gaps identified in order to further refine the risk assessment on TTXs. The present review aims to summarize the knowledge obtained towards addressing these recommendations in the two years following publication of the EFSA opinion, at the same time highlighting the points requiring further investigation. [ABSTRACT FROM AUTHOR]