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Palytoxin (PlTX) is one of the most toxic non-protein molecules extracted from soft corals, posing significant risks within the food chain. To mitigate these risks, regulatory agencies prioritize developing reliable analytical techniques for monitoring and risk management of PlTX in marine organisms. The analysis of PlTX using liquid chromatography-tandem mass spectrometry (LC/MS/MS) has become a preferred method due to its high sensitivity and specificity. However, previous studies have reported challenges in achieving sharp peak shapes and adequate resolution in PlTX detection, which can compromise the accuracy and reliability of quantification. Therefore, PlTX monitoring is actively performed using an emerging and enhanced LC/MS/MS method. To ensure accurate quantification of PlTX, which is present in trace amounts in marine organisms, it is essential to optimize chromatographic separation and ionization. In this study, we optimized the separation conditions to improve PlTX quantification through the adjustment of a buffer system, specifically increasing the concentration of ammonium formate using reverse-phase liquid chromatography coupled with multiple reaction-monitoring mass spectrometry (RPLC/MRM-MS). This optimization significantly improved peak sharpness and resolution, enhancing the overall analytical performance of LC–MS/MS for PlTX detection in marine samples. Our findings suggest that the optimized method can serve as a reliable reference for developing standardized protocols aimed at improving PlTX analysis. [ABSTRACT FROM AUTHOR]

Over the past few decades, various marine biotoxins, including paralytic shellfish poison, diarrheal shellfish poison, neurotoxic shellfish poison, and amnestic shellfish poison, have become international oceanographic concerns. These toxins are closely linked to global warming and the subsequent northward migration of toxic marine organisms, such as microalgae, fish, and benthic invertebrates, from tropical and subtropical regions. In South Korea, the bioaccumulation of marine biotoxins and incidents of seafood poisoning have also emerged as critical issues. Clear evidence indicates that the presence of toxic marine organisms in Korean coastal waters has increased, likely due to recent increases in seawater temperature. Since 2020, supported by the Ministry of Food and Drug Safety, the R&D project ‘Establishment of the Safety Management System for Marine Biotoxins’ has been carried out. This project aims to identify various regulated and unregulated marine biotoxins present in Korean coastal waters and seafood. This comprehensive project encompasses: (1) analytical methods, (2) causative organisms, (3) seafood contamination status, (4) novel and rapid detection method, (5) alternative toxicity testing method, (6) standard materials, and (7) risk assessment. The purpose of this special issue is to share the accumulated knowledge and technological advancements related to marine biotoxins by Korean researchers. The issue includes nine papers covering various types of marine biotoxins, as well as innovative bioassays and rapid detection kits. Additionally, it covers topics such as risk assessment and biotoxin management to ensure the safety of marine products. [ABSTRACT FROM AUTHOR]

Okadaic acid (OA) is one of the most potent marine biotoxins, causing diarrheal shellfish poisoning (DSP). The proliferation of microalgae that produce OA and its analogues is frequent, threatening human health and socioeconomic development. Several methods have been tested to remove this biotoxin from aquatic systems, yet none has proven enough efficacy to solve the problem. In this work, we synthesized and characterized low-cost composites and tested their efficacy for OA adsorption in saltwater. For the synthesis of the composites, the following starting materials were considered: chitosan of low and medium molecular weight (CH-LW and CH-MW, respectively), activated carbon (AC), and montmorillonite (MMT). Characterization by vibrational spectroscopy (FTIR), X-ray diffraction (XRD), and microscopy revealed differences in the mode of interaction of CH-LW and CH-MW with AC and MMT, suggesting that the interaction of CH-MW with MMT has mainly occurred on the surface of the clay particles and no sufficient intercalation of CH-MW into the MMT interlayers took place. Among the composites tested (CH-LW/AC, CH-MW/AC, CH-MW/AC/MMT, and CH-MW/MMT), CH-MW/MMT was the one that revealed lower OA adsorption efficiency, given the findings evidenced by the structural characterization. On the contrary, the CH-MW/AC composite revealed the highest average percentage of OA adsorption (53 ± 11%). Although preliminary, the results obtained in this work open up good perspectives for the use of this type of composite material as an adsorbent in the removal of OA from marine environments. [ABSTRACT FROM AUTHOR]

Marine biotoxins (MBs), harmful metabolites of marine organisms, pose a significant threat to marine ecosystems and human health due to their diverse composition and widespread occurrence. Consequently, rapid and efficient detection technology is crucial for maintaining marine ecosystem and human health. In recent years, rapid detection technology has garnered considerable attention for its pivotal role in identifying MBs, with advancements in sensitivity, specificity, and accuracy. These technologies offer attributes such as speed, high throughput, and automation, thereby meeting detection requirements across various scenarios. This review provides an overview of the classification and risks associated with MBs. It briefly outlines the current research status of marine biotoxin biosensors and introduces the fundamental principles, advantages, and limitations of optical, electrochemical, and piezoelectric biosensors. Additionally, the review explores the current applications in the detection of MBs and presents forward-looking perspectives on their development, which aims to be a comprehensive resource for the design and implementation of tailored biosensors for effective MB detection. [ABSTRACT FROM AUTHOR]

Spirolides (SPXs), gymnodimines (GYMs), and pinnatoxins (PnTXs) have been detected in shellfish from the northwestern Mediterranean coast of Spain. Several samples of bivalves were collected from Fangar Bay and Alfacs Bay in Catalonia over a period of over 7 years (from 2015 to 2021). Shellfish samples were analyzed for cyclic imines (CIs) on an LC1200 Agilent and 3200 QTrap triple–quadrupole mass spectrometer. In shellfish, SPX-1 was detected in two cases (of 26.5 µg/kg and 34 µg/kg), and GYM-A was only detected in trace levels in thirteen samples. Pinnatoxin G (PnTX-G) was detected in 44.6% of the samples, with its concentrations ranging from 2 µg/kg to 38.4 µg/kg. Statistical analyses revealed that seawater temperature influenced the presence or absence of these toxins. PnTX-G showed an extremely significant presence/temperature relationship in both bays in comparison to SPX-1 and GYM-A. The prevalence of these toxins in different bivalve mollusks was evaluated. A seasonal pattern was observed, in which the maximum concentrations were found in the winter months for SPX-1 and GYM-A but in the summer months for PnTX-G. The obtained results indicate that it is unlikely that CIs in the studied area pose a potential health risk through the consumption of a seafood diet. However, further toxicological information about CIs is necessary in order to perform a conclusive risk assessment. [ABSTRACT FROM AUTHOR]

People who consume high quantities of seafood are at a heightened risk for marine biotoxin exposure. Coastal Indigenous peoples may experience higher levels of risk than the general population due to their reliance on traditional marine foods. Most evidence on the health risks associated with biotoxins focus on a single exposure at one point in time. There is limited research on other types of exposures that may occur among those who regularly consume large quantities of seafood. The objective of this review is to assess what is known about the unique biotoxin exposure risks associated with the consumption patterns of many coastal Indigenous populations. These risks include [1]: repeated exposure to low doses of a single or multiple biotoxins [2]; repeated exposures to high doses of a single or multiple biotoxins; and [3] exposure to multiple biotoxins at a single point in time. We performed a literature search and collected 23 recent review articles on the human health effects of different biotoxins. Using a narrative framework synthesis approach, we collated what is known about the health effects of the exposure risks associated with the putative consumption patterns of coastal Indigenous populations. We found that the health effects of repeated low- or high-dose exposures and the chronic health effects of marine biotoxins are rarely studied or documented. There are gaps in our understanding of how risks differ by seafood species and preparation, cooking, and consumption practices. Together, these gaps contribute to a relatively poor understanding of how biotoxins impact the health of those who regularly consume large quantities of seafood. In the context of this uncertainty, we explore how known and potential risks associated with biotoxins can be mitigated, with special attention to coastal Indigenous populations routinely consuming seafood. Overall, we conclude that there is a need to move beyond the single-dose single-outcome model of exposure to better serve Indigenous communities and others who consume high quantities of seafood.

Background: Temperature, precipitation, and humidity are important factors that can influence the spread, reproduction, and survival of pathogens. Climate change affects these factors, resulting in higher air and water temperatures, increased precipitation, or water scarcity. Climate change may thus have an increasing impact on many infectious diseases. Methods: The present review considers those foodborne pathogens and toxins in animal and plant foods that are most relevant in Germany, on the basis of a selective literature review: the bacterial pathogens of the genera Salmonella, Campylobacter and Vibrio, parasites of the genera Cryptosporidium and Giardia, and marine biotoxins. Results: As climate change continues to progress, all infections and intoxications discussed here can be expected to increase in Germany. Conclusions: The expected increase in foodborne infections and intoxications presents a growing public health risk in Germany.

Okadaic acid (OA) is one of the most potent marine biotoxins, causing diarrheal shellfish poisoning (DSP). The proliferation of microalgae that produce OA and its analogues is frequent, threatening human health and socioeconomic development. Several methods have been tested to remove this biotoxin from aquatic systems, yet none has proven enough efficacy to solve the problem. In this work, we synthesized and characterized low-cost composites and tested their efficacy for OA adsorption in saltwater. For the synthesis of the composites, the following starting materials were considered: chitosan of low and medium molecular weight (CH-LW and CH-MW, respectively), activated carbon (AC), and montmorillonite (MMT). Characterization by vibrational spectroscopy (FTIR), X-ray diffraction (XRD), and microscopy revealed differences in the mode of interaction of CH-LW and CH-MW with AC and MMT, suggesting that the interaction of CH-MW with MMT has mainly occurred on the surface of the clay particles and no sufficient intercalation of CH-MW into the MMT interlayers took place. Among the composites tested (CH-LW/AC, CH-MW/AC, CH-MW/AC/MMT, and CH-MW/MMT), CH-MW/MMT was the one that revealed lower OA adsorption efficiency, given the findings evidenced by the structural characterization. On the contrary, the CH-MW/AC composite revealed the highest average percentage of OA adsorption (53 ± 11%). Although preliminary, the results obtained in this work open up good perspectives for the use of this type of composite material as an adsorbent in the removal of OA from marine environments.

Marine biotoxins (MBs), harmful metabolites of marine organisms, pose a significant threat to marine ecosystems and human health due to their diverse composition and widespread occurrence. Consequently, rapid and efficient detection technology is crucial for maintaining marine ecosystem and human health. In recent years, rapid detection technology has garnered considerable attention for its pivotal role in identifying MBs, with advancements in sensitivity, specificity, and accuracy. These technologies offer attributes such as speed, high throughput, and automation, thereby meeting detection requirements across various scenarios. This review provides an overview of the classification and risks associated with MBs. It briefly outlines the current research status of marine biotoxin biosensors and introduces the fundamental principles, advantages, and limitations of optical, electrochemical, and piezoelectric biosensors. Additionally, the review explores the current applications in the detection of MBs and presents forward-looking perspectives on their development, which aims to be a comprehensive resource for the design and implementation of tailored biosensors for effective MB detection.

Ciguatera is a major circumtropical poisoning caused by the consumption of marine fish and invertebrates contaminated with ciguatoxins (CTXs): neurotoxins produced by endemic and benthic dinoflagellates which are biotransformed in the fish food-web. We provide a history of ciguatera research conducted over the past 70 years on ciguatoxins from the Pacific Ocean (P-CTXs) and Caribbean Sea (C-CTXs) and describe their main chemical, biochemical, and toxicological properties. Currently, there is no official method for the extraction and quantification of ciguatoxins, regardless their origin, mainly due to limited CTX-certified reference materials. In this review, the extraction and purification procedures of C-CTXs are investigated, considering specific objectives such as isolating reference materials, analysing fish toxin profiles, or ensuring food safety control. Certain in vitro assays may provide sufficient sensitivity to detect C-CTXs at sub-ppb levels in fish, but they do not allow for individual identification of CTXs. Recent advances in analysis using liquid chromatography coupled with low- or high-resolution mass spectrometry provide new opportunities to identify known C-CTXs, to gain structural insights into new analogues, and to quantify C-CTXs. Together, these methods reveal that ciguatera arises from a multiplicity of CTXs, although one major form (C-CTX-1) seems to dominate. However, questions arise regarding the abundance and instability of certain C-CTXs, which are further complicated by the wide array of CTX-producing dinoflagellates and fish vectors. Further research is needed to assess the toxic potential of the new C-CTX and their role in ciguatera fish poisoning. With the identification of C-CTXs in the coastal USA and Eastern Atlantic Ocean, the investigation of ciguatera fish poisoning is now a truly global effort. [ABSTRACT FROM AUTHOR]

Shellfish sanitary controls are very important to guarantee consumer health because bivalve molluscs (BVM) are filter-feeders so they can accumulate pathogens, environmental contaminants and biotoxins produced by some algae, causing infections and food poisoning in humans after ingestion. The purpose of this work was to analyse with chemometric methods the historical data relating to routine analyses carried out by the competent authority (Liguria Local Health Unit, National Health Service) on the BVM reared in a shellfish farm located in the Gulf of La Spezia (Italy). Chemometric analysis was aimed at identifying any correlations between the variables, as well as any seasonal trends and similarities between the stations, in order to be able to provide further material for a more accurate risk assessment and to improve the monitoring organization for example by reducing sampling stations and/or sampling frequency. The dataset used included 31 variables classified as biotoxicological, microbiological and chemical variables, measured twice a week, monthly or half yearly respectively, for a total of 6 years (from 2015 to 2021), on samples of Mytilus galloprovincialis coming from 7 monitoring stations. The results obtained by the application of principal component analysis have shown positive alga-biotoxin correlations, as well as seasonal trends linked to algae growth, with a greater algal biomass and their toxins during the spring months. In addition, periods characterised by low rainfall were found to affect algal development, promoting especially species such as Dinophysis spp. Considering the microbiological and biotoxicological variables, significant differences between the monitoring stations were not found. However, stations could be distinguished on the basis of the nature of the predominant chemical pollutants.

Objective To construct a cardiovascular chip model for evaluating the damage of vascular glycocalyx induced by four marine toxins: okadaic acid (OA), conotoxin (CTX), tetrodotoxin (TTX) and gymnodimine (GYM), and explore the protective effect of triptolide on toxin-induced injury. Methods Human umbilical vein endothelial cells（HUVEC) were inoculated into a three-channel microfluidic chip. CCK-8 method and immunofluorescence staining were used to analyze the damage of cell viability and glycocalyx tissue induced by low, middle and high concentrations of marine toxin, as well as the protective effect of triptolide on toxin-induced injury. Results The cells in the cardiovascular chip grew well and had structurally intact glycocalyx. Compared with the control group, the activity of HUVEC cells were inhibited in group of the medium and high concentration of OA and high concentration of GYM (P<0.05). The activity of cells had not been inhibited by CTX and TTX significantly, but all the four toxins caused serious damage to the glycocalyx tissue (P<0.01). After pre-protection with triptolide, the toxicity of the four toxins to HUVEC cells and the damage rate of glycocalyx decreased significantly. Conclusion The four marine biotoxins could damage the activity and glycocalyx of HUVEC cells in a dose-dependent manner, while triptolide has a protective effect on HUVEC cells injured by toxin. [ABSTRACT FROM AUTHOR]

A significant spread and prevalence of algal toxins and, in particular, marine biotoxins have been observed worldwide over the last decades. Marine biotoxins are natural contaminants produced during harmful algal blooms being accumulated in seafood, thus representing a threat to human health. Significant progress has been made in the last few years in the development of analytical methods able to evaluate and characterize the different toxic analogs involved in the contamination, Liquid Chromatography coupled to different detection modes, including Mass Spectrometry, the method of choice due to its potential for separation, identification, quantitation and even confirmation of the different above-mentioned analogs. Despite this, the risk characterization in humans is still limited, due to several reasons, including the lack of reference materials or even the limited access to biological samples from humans intoxicated during these toxic events and episodes, which hampered the advances in the evaluation of the metabolites responsible for the toxicity in humans. Mass Spectrometry has been proven to be a very powerful tool for confirmation, and in fact, it is playing an important role in the characterization of the new biotoxins analogs. The toxin metabolization in humans is still uncertain in most cases and needs further research in which the implementation of Mass Spectrometric methods is critical. This review is focused on compiling the most relevant information available regarding the metabolization of several marine biotoxins groups, which were identified using Mass Spectrometry after the in vitro exposition of these toxins to liver microsomes and hepatocytes. Information about the presence of metabolites in human samples, such as human urine after intoxication, which could also be used as potential biomarkers for diagnostic purposes, is also presented. [ABSTRACT FROM AUTHOR]

Bivalves are a high-value product whose production has markedly increased, reaching 9863 tonnes in Portugal in 2021. Bivalves' habitats—lagoons, estuaries and coastal waters—are exposed to biological and anthropogenic contaminants, which can bioaccumulate in these organisms and pose a significant public health risk. The need to obtain a safe product for human consumption led to the implementation of standardised hygiene regulations for harvesting and marketing bivalve molluscs, resulting in routine monitoring of bivalve production areas for microbial quality, metal contaminants, and marine biotoxins. While excessive levels of biotoxins and metal contamination lead to temporary harvesting bans, high faecal contamination leads to area reclassification and impose post-harvest treatments. In this study, the seasonal and temporal variability of these parameters were analysed using historical data generated by the monitoring programme during the last decade. Moreover, the impact of the monitoring program on bivalve harvesting from 2011 to 2020 was assessed. This program presented a considerable improvement over time, with an increase in the sampling effort and the overall program representativeness. Finally, contamination risk, revising control measures, and defining recommendations for risk mitigation measures are given in the light of ten years' monitoring. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX) is a potent neurotoxin responsible for a human intoxication event in Spain associated with the consumption of trumpet shell Charonia lampas. In Europe, TTX is not regulated or monitored, and there is little knowledge about its presence in seafood. Here, we investigated the tissue distribution of TTX and analogues in three specimens of trumpet shell C. lampas bought in a market in southern Portugal. Toxin concentration was above the EFSA recommended limit in the non-edible tissues of all specimens and within the limit in the edible tissues of two specimens. 4,9-AnhydroTTX and 13 additional TTX analogues were detected in tissues, the most abundant being anhydrotrideoxyTTX and trideoxyTTX. These results suggest that although thorough evisceration may lower the amount of TTX consumed, it may not be sufficient to ensure consumer safety. Regular monitoring of TTX and analogues in trumpet shell and other edible gastropods is therefore recommended to avoid poisoning incidents. [ABSTRACT FROM AUTHOR]

During the development and senescence of harmful algal blooms (HAB), most of the algae cells not ingested by grazers or filter-feeding organisms sink to the bottom, making sediments important reservoirs of algae toxins. In this study, lipophilic marine toxins were determined in the sediments collected from depths ranging from 5 to 145 m depth in the marine protected area of Arrábida (southwest Portuguese coast). Sediments were characterized in terms of granulometry, water and organic matter content. The toxins were determined by liquid chromatography with tandem mass spectrometry. Okadaic acid (OA), dinophysistoxin-2 (DTX2), and azaspiracid-2 (AZA2), reaching concentrations up to 3.4, 1.3, and 0.13 ng/g, respectively, were found. A trend in the occurrence of DTX2 and AZA2 with sediment water and organic matter content was observed, as well as with AZA2 and depth. This study highlights the need to further investigate sediment deposition of toxins and their availability for bottom-dwelling organisms and its contamination. • First record of lipophilic marine toxins in sediments from Portugal • OA, DTX-2 and AZA-2 were determined. • Sediment water content, organic matter and depth may influence toxins levels. [ABSTRACT FROM AUTHOR]

Spirolides (SPXs), gymnodimines (GYMs), and pinnatoxins (PnTXs) have been detected in shellfish from the northwestern Mediterranean coast of Spain. Several samples of bivalves were collected from Fangar Bay and Alfacs Bay in Catalonia over a period of over 7 years (from 2015 to 2021). Shellfish samples were analyzed for cyclic imines (CIs) on an LC1200 Agilent and 3200 QTrap triple–quadrupole mass spectrometer. In shellfish, SPX-1 was detected in two cases (of 26.5 µg/kg and 34 µg/kg), and GYM-A was only detected in trace levels in thirteen samples. Pinnatoxin G (PnTX-G) was detected in 44.6% of the samples, with its concentrations ranging from 2 µg/kg to 38.4 µg/kg. Statistical analyses revealed that seawater temperature influenced the presence or absence of these toxins. PnTX-G showed an extremely significant presence/temperature relationship in both bays in comparison to SPX-1 and GYM-A. The prevalence of these toxins in different bivalve mollusks was evaluated. A seasonal pattern was observed, in which the maximum concentrations were found in the winter months for SPX-1 and GYM-A but in the summer months for PnTX-G. The obtained results indicate that it is unlikely that CIs in the studied area pose a potential health risk through the consumption of a seafood diet. However, further toxicological information about CIs is necessary in order to perform a conclusive risk assessment.

In continental Portugal, high levels of diarrhetic shellfish poisoning toxins (DSTs) and paralytic shellfish poisoning toxins (PSTs) can be accumulated in bivalves. DSTs presented maxima during the dry summer season and were linearly related to precipitation accumulated over the previous months. Precipitation is highest on the northwest (NW) than on the southwest (SW) or south (S) coasts. An NW to S decreasing gradient in DSTs is commonly found. An NW to S decreasing gradient can also be found for some macronutrients (N, P and Si). Coastal fertilisation also favoured contamination with ASTs (amnesic shellfish poisoning toxins) and PSTs mainly on the NW coast, followed by the SW coast, with the lowest contaminations found on the S coast. Despite its marked autumnal seasonality, PSTs were unpredictable interannually. High PST’s contamination was coincidental with the last four solar minima periods of the 11-year sunspot cycle. On the opposite, ASTs increased slightly during maxima of geomagnetic activity (GMA). AST incidence in April and October was 2.7 times higher when GMA was above the monthly average (18.5 nT) in March and September, respectively. In the last two decades (2001–2020), average DST levels in June + July reduced after 2008, following a trend in the reduction of precipitation after 2003. Nevertheless, no trends were observed in the average percentage of samples exceeding annually the regulatory limit (PSEARL) for DSTs (18.4%) due to the high percentage of indicator-species analysed, which maintain DSTs for a prolonged time. Despite the low average PSEARL of 1.0% for ASTs during 2001–2013, it reduced to 0.4% in 2014–2020. This might have been coincidental with a global change in the northern hemisphere ocean temperature anomaly in 2014 or with weaker GMA stimulation during the weaker solar cycle 24. Due to the large interannual variability in PSTs associated with the solar cycle, no average PSEARL can be defined and no clear trends can be associated with global change. [ABSTRACT FROM AUTHOR]

Saxitoxin and its more than 50 analogues are a group of naturally occurring neurotoxins collectively designated as paralytic shellfish toxins (PSTs). PSTs are toxic to humans and maximum legal limits in seafood have been implemented by regulatory authorities worldwide. In the European Union, monitoring of PSTs is performed using the AOAC Official Method 2005.06, based on liquid chromatography coupled with fluorescence detection (LC- FLD). However, this method has been suggested to not effectively detect the emerging C-11 hydroxyl (M-toxins) and benzoate (GC-toxins) analogues, with these analogues currently not being surveyed in monitoring programs. In this study, a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was used to search for these emerging PSTs in mussels, Mytilus galloprovincialis, contaminated following an intense Gymnodinium catenatum bloom in the Tagus estuary (Lisbon, Portugal). Five M-toxins (M1, M2, M6, dcM6, and dcM10), but no GC-toxins, were detected in the mussels' whole-soft body tissue. Moreover, the classical PSTs (C1 to C4, GTX 4 to GTX6, dcGTX1 to dcGTX4, dcSTX, dcNEO, and STX) were also found and comprised the largest fraction of the PSTs' profile. The presence of unregulated PSTs in edible mussel samples suggests potential seafood safety risks and urges further research to determine the frequency of these analogues in seafood and their contribution to toxicity. [ABSTRACT FROM AUTHOR]

The contaminant responsible for the atypical toxicity reported in mussels from Bizerte Lagoon (Northern Tunisia) during the last decade has been characterized as C17-sphinganine analog mycotoxin (C17-SAMT). This neurotoxin showed common mouse toxic symptoms, including flaccid paralysis and severe dyspnea, followed by rapid death. For hazard assessment on human health, in this work we aimed to evaluate the in vivo genotoxic effects of this marine biotoxin using the classical alkaline and modified Fpg comet assays performed to detect DNA breaks and alkali-labile sites as well as oxidized bases. The micronucleus assay was used on bone marrow to detect chromosome and genome damage. C17-SAMT induces a statistically insignificant increase in DNA tail intensity at all doses in the duodenum, and in the spleen contrary to the liver, the percentage of tail DNA increased significantly at the mid dose of 300 µg/kg b.w/d. C17-SAMT did not affect the number of micronuclei in the bone marrow. Microscopic observations of the liver showed an increase in the number of mitosis and hepatocytes' cytoplasm clarification. At this level of study, we confirm that C17-SAMT induced DNA damage in the liver but there was no evidence of effects causing DNA oxidation or chromosome and genome damage. [ABSTRACT FROM AUTHOR]

This study examined data from the Centers for Disease Control and Prevention's National Outbreak Reporting System between 2001 and 2021 for confirmed outbreaks of foodborne illness due to Ciguatoxin in the United States. Previous research into Ciguatoxin illness in the United States has focused on specific states or territories-namely Hawaii, Florida, Puerto Rico, and the Virgin Islands-meaning the national distribution of outbreaks remains unclear. In addition, while specific categories of seafood (e.g., reef fish) are known to carry elevated risk of illness due to Ciguatoxin poisoning, it remains unclear the extent to which specific seafood items are associated with the odds of being hospitalized in an outbreak. This study calculated descriptive statistics for the distribution of outbreaks by state, season, site of exposure, and implicated seafood item. Then, binomial regression was used to assess the relationship between the implicated seafood item in an outbreak and hospitalization. Results provided evidence that knowing the implicated seafood item in an outbreak is associated with the odds of hospitalization (χ 2 5 = 33.023, p < 0.0001). Even when a seafood item was found to be associated with elevated odds of hospitalization, not all cases involved hospitalization. This finding aligns with Ciguatoxin poisoning case reports, noting that key epidemiological factors include not just the seafood item consumed but also the quantity and the part consumed (e.g., the head). In conclusion, public health officials should consider Ciguatoxin poisoning outbreaks as multidimensional and utilize information about the seafood consumed as well as the quantity and parts of the seafood consumed.

Ciguatera is a major circumtropical poisoning caused by the consumption of marine fish and invertebrates contaminated with ciguatoxins (CTXs): neurotoxins produced by endemic and benthic dinoflagellates which are biotransformed in the fish food-web. We provide a history of ciguatera research conducted over the past 70 years on ciguatoxins from the Pacific Ocean (P-CTXs) and Caribbean Sea (C-CTXs) and describe their main chemical, biochemical, and toxicological properties. Currently, there is no official method for the extraction and quantification of ciguatoxins, regardless their origin, mainly due to limited CTX-certified reference materials. In this review, the extraction and purification procedures of C-CTXs are investigated, considering specific objectives such as isolating reference materials, analysing fish toxin profiles, or ensuring food safety control. Certain in vitro assays may provide sufficient sensitivity to detect C-CTXs at sub-ppb levels in fish, but they do not allow for individual identification of CTXs. Recent advances in analysis using liquid chromatography coupled with low- or high-resolution mass spectrometry provide new opportunities to identify known C-CTXs, to gain structural insights into new analogues, and to quantify C-CTXs. Together, these methods reveal that ciguatera arises from a multiplicity of CTXs, although one major form (C-CTX-1) seems to dominate. However, questions arise regarding the abundance and instability of certain C-CTXs, which are further complicated by the wide array of CTX-producing dinoflagellates and fish vectors. Further research is needed to assess the toxic potential of the new C-CTX and their role in ciguatera fish poisoning. With the identification of C-CTXs in the coastal USA and Eastern Atlantic Ocean, the investigation of ciguatera fish poisoning is now a truly global effort.

Paralytic Shellfish Toxins (PSTs) are marine biotoxins, primarily produced by dinoflagellates of the genera Gymnodinium spp., Alexandrium spp. They can accumulate in shellfish and, through the food chain, be assimilated by humans, giving rise to Paralytic Shellfish Poisoning. The maximum permitted level for PSTs in bivalves is 800 μg STX·2HCl eqv/kg (Reg. EC N° 853/2004). Until recently, the reference analytical method was the Mouse Bioassay, but Reg. EU N° 1709/2021 entered into force on 13 October 2021 and identified in the Standard EN14526:2017 or in any other internationally recognized validated method not entailing the use of live animals as official methods. Then the official control laboratories had urgently to fulfill the new requests, face out the Mouse Bioassay and implement instrumental analytical methods. The "EURLMB SOP for the analysis of PSTs by pre-column HPLC-FLD according to OMA AOAC 2005.06" also introduced a simplified semiquantitative approach to discriminate samples above and below the regulatory limit. The aim of the present paper is to present a new presence/absence test with a cut-off at 600 μg STX·2HCl eqv/kg enabling the fast discrimination of samples with very low PSTs levels from those to be submitted to the full quantitative confirmatory EN14526:2017 method. The method was implemented, avoiding the use of a large number of certified reference standards and long quantification procedures, resulting in an efficient, economical screening instrument available for official control laboratories. The protocol was fully validated, obtaining good performances in terms of repeatability (<11%) and recovery (53–106%) and accredited according to ISO/IEC 17025. The method was applied to mollusks collected from March 2021 to February 2022 along the Marche region in the frame of marine toxins official control. [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.

Ciguatoxins (CTXs) are a group of marine biotoxins, consisting of over 30 different congeners that can contaminate marine food webs. Generally, the molecular structures among the known congeners are variable by geographical region (i.e., ocean basin) and vector species. Limited information is available regarding the CTX profiles among or within CTX vector species and their capture regions. Within this study, an in-depth investigation based on a semi-targeted LC-MS/MS approach was conducted to investigate 52 tissue samples from a single species Lutjanus bohar (Lutjanidae), a common CTX vector, sourced from two distinct regions (Indian Ocean and Pacific Ocean). All samples revealed the presence of a complex CTX contaminant profile, with samples containing several congeners of the CTX3C-group (2,3,51-trihydroxyCTX3C, 2,3,-dihydroxyCTX3C, 2-hydroxyCTX3C, M-seco-CTX3C, 51-hydroxyCTX3C, CTX3C, and respective 49-epimers in most cases). All samples were previously found to possess a CTX-like toxicity within an in vitro cytotoxicity assay (N2a-bioassay), demonstrating the relevance of CTX3C-group congeners with regard to ciguatera poisoning. Individual samples contained an indistinguishable toxin profile within the species and among the distinct oceanic capture regions. These findings imply either a species-specific CTX metabolism or the emergence of an interoceanic CTX toxin profile. The inter-regional CTX profile demonstrated here provides further evidence that classifying CTX congeners based on ocean basins may be imprecise.

Bivalves are a high-value product whose production has markedly increased, reaching 9863 tonnes in Portugal in 2021. Bivalves’ habitats—lagoons, estuaries and coastal waters—are exposed to biological and anthropogenic contaminants, which can bioaccumulate in these organisms and pose a significant public health risk. The need to obtain a safe product for human consumption led to the implementation of standardised hygiene regulations for harvesting and marketing bivalve molluscs, resulting in routine monitoring of bivalve production areas for microbial quality, metal contaminants, and marine biotoxins. While excessive levels of biotoxins and metal contamination lead to temporary harvesting bans, high faecal contamination leads to area reclassification and impose post-harvest treatments. In this study, the seasonal and temporal variability of these parameters were analysed using historical data generated by the monitoring programme during the last decade. Moreover, the impact of the monitoring program on bivalve harvesting from 2011 to 2020 was assessed. This program presented a considerable improvement over time, with an increase in the sampling effort and the overall program representativeness. Finally, contamination risk, revising control measures, and defining recommendations for risk mitigation measures are given in the light of ten years’ monitoring.

A significant spread and prevalence of algal toxins and, in particular, marine biotoxins have been observed worldwide over the last decades. Marine biotoxins are natural contaminants produced during harmful algal blooms being accumulated in seafood, thus representing a threat to human health. Significant progress has been made in the last few years in the development of analytical methods able to evaluate and characterize the different toxic analogs involved in the contamination, Liquid Chromatography coupled to different detection modes, including Mass Spectrometry, the method of choice due to its potential for separation, identification, quantitation and even confirmation of the different above-mentioned analogs. Despite this, the risk characterization in humans is still limited, due to several reasons, including the lack of reference materials or even the limited access to biological samples from humans intoxicated during these toxic events and episodes, which hampered the advances in the evaluation of the metabolites responsible for the toxicity in humans. Mass Spectrometry has been proven to be a very powerful tool for confirmation, and in fact, it is playing an important role in the characterization of the new biotoxins analogs. The toxin metabolization in humans is still uncertain in most cases and needs further research in which the implementation of Mass Spectrometric methods is critical. This review is focused on compiling the most relevant information available regarding the metabolization of several marine biotoxins groups, which were identified using Mass Spectrometry after the in vitro exposition of these toxins to liver microsomes and hepatocytes. Information about the presence of metabolites in human samples, such as human urine after intoxication, which could also be used as potential biomarkers for diagnostic purposes, is also presented.

Marine biotoxins are metabolites produced by algae that can accumulate in shellfish or fish and enter organisms through the food chain, posing a serious threat to biological health. Therefore, accurate and rapid detection is an urgent requirement for food safety. Although various detection methods, including the mouse bioassay, liquid chromatography-mass spectrometry, and cell detection methods, and protein phosphatase inhibition assays have been developed in the past decades, the current detection methods cannot fully meet these demands. Among these methods, the outstanding immunoassay virtues of high sensitivity, reliability, and low cost are highly advantageous for marine biotoxin detection in complex samples. In this work, we review the recent 5-year progress in marine biotoxin immunodetection technologies such as optical immunoassays, electrochemical immunoassays, and piezoelectric immunoassays. With the assistance of immunoassays, the detection of food-related marine biotoxins can be implemented for ensuring public health and preventing food poisoning. In addition, the immunodetection technique platforms including lateral flow chips and microfluidic chips are also discussed. We carefully investigate the advantages and disadvantages for each immunoassay, which are compared to demonstrate the guidance for selecting appropriate immunoassays and platforms for the detection of marine biotoxins. It is expected that this review will provide insights for the further development of immunoassays and promote the rapid progress and successful translation of advanced immunoassays with food safety detection.

Saxitoxin and its more than 50 analogues are a group of naturally occurring neurotoxins collectively designated as paralytic shellfish toxins (PSTs). PSTs are toxic to humans and maximum legal limits in seafood have been implemented by regulatory authorities worldwide. In the European Union, monitoring of PSTs is performed using the AOAC Official Method 2005.06, based on liquid chromatography coupled with fluorescence detection (LC- FLD). However, this method has been suggested to not effectively detect the emerging C-11 hydroxyl (M-toxins) and benzoate (GC-toxins) analogues, with these analogues currently not being surveyed in monitoring programs. In this study, a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was used to search for these emerging PSTs in mussels, Mytilus galloprovincialis, contaminated following an intense Gymnodinium catenatum bloom in the Tagus estuary (Lisbon, Portugal). Five M-toxins (M1, M2, M6, dcM6, and dcM10), but no GC-toxins, were detected in the mussels’ whole-soft body tissue. Moreover, the classical PSTs (C1 to C4, GTX 4 to GTX6, dcGTX1 to dcGTX4, dcSTX, dcNEO, and STX) were also found and comprised the largest fraction of the PSTs’ profile. The presence of unregulated PSTs in edible mussel samples suggests potential seafood safety risks and urges further research to determine the frequency of these analogues in seafood and their contribution to toxicity.

The contaminant responsible for the atypical toxicity reported in mussels from Bizerte Lagoon (Northern Tunisia) during the last decade has been characterized as C17-sphinganine analog mycotoxin (C17-SAMT). This neurotoxin showed common mouse toxic symptoms, including flaccid paralysis and severe dyspnea, followed by rapid death. For hazard assessment on human health, in this work we aimed to evaluate the in vivo genotoxic effects of this marine biotoxin using the classical alkaline and modified Fpg comet assays performed to detect DNA breaks and alkali-labile sites as well as oxidized bases. The micronucleus assay was used on bone marrow to detect chromosome and genome damage. C17-SAMT induces a statistically insignificant increase in DNA tail intensity at all doses in the duodenum, and in the spleen contrary to the liver, the percentage of tail DNA increased significantly at the mid dose of 300 µg/kg b.w/d. C17-SAMT did not affect the number of micronuclei in the bone marrow. Microscopic observations of the liver showed an increase in the number of mitosis and hepatocytes’ cytoplasm clarification. At this level of study, we confirm that C17-SAMT induced DNA damage in the liver but there was no evidence of effects causing DNA oxidation or chromosome and genome damage.

Paralytic Shellfish Toxins (PSTs) are marine biotoxins, primarily produced by dinoflagellates of the genera Gymnodinium spp., Alexandrium spp. They can accumulate in shellfish and, through the food chain, be assimilated by humans, giving rise to Paralytic Shellfish Poisoning. The maximum permitted level for PSTs in bivalves is 800 μg STX·2HCl eqv/kg (Reg. EC N° 853/2004). Until recently, the reference analytical method was the Mouse Bioassay, but Reg. EU N° 1709/2021 entered into force on 13 October 2021 and identified in the Standard EN14526:2017 or in any other internationally recognized validated method not entailing the use of live animals as official methods. Then the official control laboratories had urgently to fulfill the new requests, face out the Mouse Bioassay and implement instrumental analytical methods. The “EURLMB SOP for the analysis of PSTs by pre-column HPLC-FLD according to OMA AOAC 2005.06” also introduced a simplified semiquantitative approach to discriminate samples above and below the regulatory limit. The aim of the present paper is to present a new presence/absence test with a cut-off at 600 μg STX·2HCl eqv/kg enabling the fast discrimination of samples with very low PSTs levels from those to be submitted to the full quantitative confirmatory EN14526:2017 method. The method was implemented, avoiding the use of a large number of certified reference standards and long quantification procedures, resulting in an efficient, economical screening instrument available for official control laboratories. The protocol was fully validated, obtaining good performances in terms of repeatability (

It is undeniable that with the popularity of sushi and sashimi over the last decade the consumption of raw fish has extremely increased. Raw fish is very appreciated worldwide and has become a major component of human diet because of its fine taste and nutritional properties. Possible hazards concerning fish safety and quality are classified as biological and chemical hazards. They are contaminants that often accumulate in edible tissue of fish and transmit to humans via the food chain affecting the consumer's health. Although their concentration in fish and fishery products are found at non-alarming level of a daily basis period, they induce hazardous outcome on human health due to long and continuous consumption of raw fish. Regular sushi and sashimi eaters have to be aware of the contaminants found in the other components of their dish that often add up to acceptable residue limits found in fish. Hence, there is the urge for effective analytical methods to be developed as well as stricter regulations to be put in force between countries to monitor the safety and quality of fish for the interest of public health. [ABSTRACT FROM AUTHOR]

The occurrence and variability of domoic acid (DA) levels in wild Mytilus galloprovincialis samples, compared with the Pseudo-nitzschia spp. abundance and particulate DA (pDA) concentrations in relation to the environmental changes in the Golden Horn Estuary, Turkey from October 2018 to September 2019. Biotoxin analysis were performed by high-performance liquid chromatography with diode-array detection (HPLC–DAD). DA concentrations in particulate matter (pDA) and mussel samples were found between 0.090–0.685 µg L−1 and 0.905–2.413 µg g−1, respectively. Accumulation of DA in wild mussel samples could be the result of the increasing tendency of P.nitzschia spp. abundances between April and May. Maximum DA levels were detected in particulate matter when the salinity was measured as the lowest in May. Thus, it can be said that the DA production was driven by the significant salinity decrease in the GHE. This is the first attempt regarding the presence of DA in M. galloprovincialis samples collected from Turkish coasts. [ABSTRACT FROM AUTHOR]

Saxitoxin, which is one of the most typical paralytic shellfish poisoning toxins, ranks the highest intoxication rate of marine biological poisoning cases globally. Efficient clean‐up and extraction of saxitoxin from complex biological matrices are imperative for the analysis and concentration monitoring of the toxin when correlative poisoning cases happen. Herein, l‐cysteine‐modified magnetic microspheres based on metal‐organic coordination were synthesized by a facile approach and applied for magnetic solid‐phase extraction of saxitoxin from rat plasma samples before liquid chromatography–tandem mass spectrometry detection. Parameters, including adsorbent amount, extraction time, desorption solution, and desorption time that could affect the extraction efficiency, were respectively investigated. The developed method demonstrated good linearity in the range of 5–300 ng/mL (R2 = 0.9985) with a limit of quantification of 5 ng/mL and a limit of detection of 0.5 ng/mL, acceptable accuracy. and precision of within‐run and between‐run. [ABSTRACT FROM AUTHOR]

• The first purported images of ciguatoxin-3C by Electron Microscopy. • Proof-of-principle for broad method applicability towards expansive classes of marine biotoxins. • Describes how existing advanced instruments can use this method to achieve higher resolution. • Advances human health and toxin discovery goals for ciguatera poisoning. • Provides details for improving the method to achieve toxin specificity using antibodies. Marine biotoxins in seafood products are responsible for human illnesses and seafood production losses. Ciguatera poisoning (CP) is the most commonly reported non-bacterial seafood-related illness worldwide and is caused by the consumption of fish or shellfish containing ciguatoxins (CTXs), a class of polycyclic polyether marine biotoxins with highly complex chemical structures. Reliable laboratory testing in clinical samples for CTXs is not available and many analogues remain structurally unresolved. CTXs have a proposed backbone size of 3 nm but have never been directly observed. Herein, the first purported images of CTX-3C obtained by Cryogenic Electron Microscopy (Cryo-EM) and in the presence of gold nanoparticles with attached antibodies by Transmission Electron Microscopy (TEM) are presented. TEM image was captured based on a sample preparation optimization technique using anti-ciguatoxins CTX-3C [1C49] Ab00350–1.1 purified antibodies, gold nanoparticles, and a concentration of synthetic CTX-3C molecules combined for imaging. We discuss how other existing instrumentations with atomic resolutions exceeding <0.1 nm could be applied using this preparatory method to observe, with greater detail, the common backbone of all known CTXs and its proposed wider adoption towards other marine biotoxins. Conventional detection methods for marine toxins have drawbacks, applying cutting-edge existing technologies such as TEMs to directly observe never-before-seen marine toxins can contribute to the fundamental science of marine toxins research. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent decades, more than 130 potentially toxic metabolites originating from dinoflagellate species belonging to the genus Karenia or metabolized by marine organisms have been described. These metabolites include the well-known and large group of brevetoxins (BTXs), responsible for foodborne neurotoxic shellfish poisoning (NSP) and airborne respiratory symptoms in humans. Karenia spp. also produce brevenal, brevisamide and metabolites belonging to the hemi-brevetoxin, brevisin, tamulamide, gymnocin, gymnodimine, brevisulcenal and brevisulcatic acid groups. In this review, we summarize the available knowledge in the literature since 1977 on these various identified metabolites, whether they are produced directly by the producer organisms or biotransformed in marine organisms. Their structures and physicochemical properties are presented and discussed. Among future avenues of research, we highlight the need for more toxin occurrence data with analytical techniques, which can specifically determine the analogs present in samples. New metabolites have yet to be fully described, especially the groups of metabolites discovered in the last two decades (e.g tamulamides). Lastly, this work clarifies the different nomenclatures used in the literature and should help to harmonize practices in the future.

Brevetoxins (BTXs) are marine biotoxins responsible for neurotoxic shellfish poisoning (NSP) after ingestion of contaminated shellfish. NSP is characterized by neurological, gastrointestinal and/or cardiovascular symptoms. The main known producer of BTXs is the dinoflagellate Karenia brevis, but other microalgae are also suspected to synthesize BTX-like compounds. BTXs are currently not regulated in France and in Europe. In November 2018, they have been detected for the first time in France in mussels from a lagoon in the Corsica Island (Mediterranean Sea), as part of the network for monitoring the emergence of marine biotoxins in shellfish. To prevent health risks associated with the consumption of shellfish contaminated with BTXs in France, a working group was set up by the French Agency for Food, Environmental and Occupational Health & Safety (Anses). One of the aims of this working group was to propose a guidance level for the presence of BTXs in shellfish. Toxicological data were too limited to derive an acute oral reference dose (ARfD). Based on human case reports, we identified two lowest-observed-adverse-effect levels (LOAELs). A guidance level of 180 µg BTX-3 eq./kg shellfish meat is proposed, considering a protective default portion size of 400 g shellfish meat.

Currently, digital technologies influence information dissemination in all business sectors, with great emphasis put on exploitation strategies. Public administrations often use information systems and establish open data repositories, primarily supporting their operation but also serving as data providers, facilitating decision-making. As such, risk analysis in the public health sector, including food safety authorities, often relies on digital technologies and open data sources. Global food safety challenges include marine biotoxins (MBs), being contaminants whose mitigation largely depends on risk analysis. Ciguatera Fish Poisoning (CFP), in particular, is a MB-related seafood intoxication attributed to the consumption of fish species that are prone to accumulate ciguatoxins. Historically, CFP occurred endemically in tropical/subtropical areas, but has gradually emerged in temperate regions, including European waters, necessitating official policy adoption to manage the potential risks. Researchers and policy-makers highlight scientific data inadequacy, under-reporting of outbreaks and information source fragmentation as major obstacles in developing CFP mitigation strategies. Although digital technologies and open data sources provide exploitable scientific information for MB risk analysis, their utilization in counteracting CFP-related hazards has not been addressed to date. This work thus attempts to answer the question, “What is the current extent of digital technologies’ and open data sources’ utilization within risk analysis tasks in the MBs field, particularly on CFP?”, by conducting a systematic literature review of the available scientific and grey literature. Results indicate that the use of digital technologies and open data sources in CFP is not negligible. However, certain gaps are identified regarding discrepancies in terminology, source fragmentation and a redundancy and downplay of social media utilization, in turn constituting a future research agenda for this under-researched topic.

People who consume high quantities of seafood are at a heightened risk for marine biotoxin exposure. Coastal Indigenous peoples may experience higher levels of risk than the general population due to their reliance on traditional marine foods. Most evidence on the health risks associated with biotoxins focus on a single exposure at one point in time. There is limited research on other types of exposures that may occur among those who regularly consume large quantities of seafood. The objective of this review is to assess what is known about the unique biotoxin exposure risks associated with the consumption patterns of many coastal Indigenous populations. These risks include [1]: repeated exposure to low doses of a single or multiple biotoxins [2]; repeated exposures to high doses of a single or multiple biotoxins; and [3] exposure to multiple biotoxins at a single point in time. We performed a literature search and collected 23 recent review articles on the human health effects of different biotoxins. Using a narrative framework synthesis approach, we collated what is known about the health effects of the exposure risks associated with the putative consumption patterns of coastal Indigenous populations. We found that the health effects of repeated low- or high-dose exposures and the chronic health effects of marine biotoxins are rarely studied or documented. There are gaps in our understanding of how risks differ by seafood species and preparation, cooking, and consumption practices. Together, these gaps contribute to a relatively poor understanding of how biotoxins impact the health of those who regularly consume large quantities of seafood. In the context of this uncertainty, we explore how known and potential risks associated with biotoxins can be mitigated, with special attention to coastal Indigenous populations routinely consuming seafood. Overall, we conclude that there is a need to move beyond the single-dose single-outcome model of exposure to better serve Indigenous communities and others who consume high quantities of seafood., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Microalgal species growing in marine and aquaculture environments can be responsible for harmful events because of their ability to produce potent natural toxins that can accumulate in edible mollusc species. Their consumption can cause severe illness and even be lethal. The European Union provides comprehensive regulations covering various general food safety aspects to manage the risk of contamination in shellfish farms. Many analytical methods have been proposed to evaluate algal toxins presence in the environment and in food products, for conducting surveillance studies of the main molluscs production sites and, where necessary, immediate monitoring of possible contamination of shellfish. In this work, a one-year analytical surveillance study was carried out to verify the possible presence of algal biotoxins in molluscs from a Mediterranean breeding area. Water and molluscs were sampled from a district of the North-East coast of Sicily, consisting of a unique brackish ecosystem of two lakes connected to each other and to the sea by narrow canals. Water samples were collected to investigate phytoplankton i by microscope analysis to assess the presence of potentially toxin-producing species, such as Pseudo-nitzschia spp, Alexandrium spp and Gonyaulax spinifera, although the presence of toxic phytoplankton has never reached alert levels. Mussels and clams samples were submitted to analysis of paralytic shellfish poisoning toxins, amnesic shellfish poisoning toxins and lipophilic toxins by liquid chromatography-based methods Only a few yessotoxins were detected, having concentrations always below the regulation limits. An existing liquid chromatography-tandem mass spectrometry-based multiresidue method for lipophilic biotoxins was adopted and extended to cover emerging biotoxins such as cyclic imines. The performance of the analytical method for Gymnodimine A and Spirolide 13-desMeC was assessed, obtaining respective quantitation limits of 20 and 10 µg kg−1, a precision always lower than 13% and trueness in the 81–120% range. Method applicability was confirmed using certified materials and a naturally contaminated sample. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) are among the most severe ecological marine problems worldwide. Under favorable climate and oceanographic conditions, toxin-producing microalgae species may proliferate, reach increasingly high cell concentrations in seawater, accumulate in shellfish, and threaten the health of seafood consumers. There is an urgent need for the development of effective tools to help shellfish farmers to cope and anticipate HAB events and shellfish contamination, which frequently leads to significant negative economic impacts. Statistical and machine learning forecasting tools have been developed in an attempt to better inform the shellfish industry to limit damages, improve mitigation measures and reduce production losses. This study presents a synoptic review covering the trends in machine learning methods for predicting HABs and shellfish biotoxin contamination, with a particular focus on autoregressive models, support vector machines, random forest, probabilistic graphical models, and artificial neural networks (ANN). Most efforts have been attempted to forecast HABs based on models of increased complexity over the years, coupled with increased multi-source data availability, with ANN architectures in the forefront to model these events. The purpose of this review is to help defining machine learning-based strategies to support shellfish industry to manage their harvesting/production, and decision making by governmental agencies with environmental responsibilities.

Tetrodotoxin (TTX) is a potent neurotoxin, considered an emerging toxin in Europe where recently a safety limit of 44 µg TTX kg−1 was recommended by authorities. In this study, three specimens of the large gastropod trumpet shell Charonia lampas bought in a market in south Portugal were analyzed using a neuroblastoma cell (N2a) based assay and by LC-MS/MS. N2a toxicity was observed in the viscera of two individuals analyzed and LC-MS/MS showed very high concentrations of TTX (42.1 mg kg−1) and 4,9-anhydroTTX (56.3 mg kg−1). A third compound with m/z 318 and structurally related with TTX was observed. In the edible portion, i.e., the muscle, toxin levels were below the EFSA recommended limit. This study shows that trumpet shell marine snails are seafood species that may reach the markets containing low TTX levels in the edible portion but containing very high levels of TTX in non-edible portion raising concerns regarding food safety if a proper evisceration is not carried out by consumers. These results highlight the need for better understanding TTX variability in this gastropod species, which is critical to developing a proper legal framework for resources management ensuring seafood safety, and the introduction of these gastropods in the markets.

Introduction: Growing consumption of shellfish is associated with an increased risk of food poisoning. The study was carried out on live bivalve molluscs available on the Polish market between 2009 and 2013. Material and Methods: ELISA was used for the determination of the following marine biotoxins: paralytic shellfish poison (PSP), amnaesic shellfish poison (ASP), and diarrhoeic shellfish poison (DSP). The molluscs, of which seven species were examined, were obtained from wholesale companies and markets. Results: Marine biotoxins were detected below the permitted levels in 67.6% of the samples. The maximum amounts of PSP and ASP biotoxins were found in great scallops (532.6 μg/kg and 1.0 mg/kg respectively) and the peak for DSP was in blue mussels (107 μg/kg). Conclusion: The analysis of toxicological status of raw bivalve molluscs available on the market in Poland indicates that they are safe for consumers.

Okadaic acid (OA) group toxins may accumulate in shellfish and can result in diarrhetic shellfish poisoning when consumed by humans, and are therefore regulated. Purified toxins are required for the production of certified reference materials used to accurately quantitate toxin levels in shellfish and water samples, and for other research purposes. An improved procedure was developed for the isolation of dinophysistoxin 2 (DTX2) from shellfish (M. edulis), reducing the number of purification steps from eight to five, thereby increasing recoveries to ~68%, compared to ~40% in a previously reported method, and a purity of >95%. Cell densities and toxin production were monitored in cultures of Prorocentrum lima, that produced OA, DTX1, and their esters, over ~1.5 years with maximum cell densities of ~70,000 cells mL−1 observed. Toxin accumulation progressively increased over the study period, to ~0.7 and 2.1 mg L−1 of OA and DTX1 (including their esters), respectively, providing information on appropriate harvesting times. A procedure for the purification of OA and DTX1 from the harvested biomass was developed employing four purification steps, with recoveries of ~76% and purities of >95% being achieved. Purities were confirmed by LC-HRMS, LC-UV, and NMR spectroscopy. Additional stability observations led to a better understanding of the chemistry of these toxins.

Only few naturally occurring cyclic imines have been fully structurally elucidated or synthesized to date. The configuration at the C-4 carbon plays a pivotal role in the neurotoxicity of many of these metabolites, for example, gymnodomines (GYMs) and spirolides (SPXs). However, the stereochemistry at this position is not accessible by nuclear Overhauser effect—nuclear magnetic resonance spectroscopy (NOE-NMR) due to unconstrained rotation of the single carbon bond between C-4 and C-5. Consequently, the relative configuration of GYMs and SPXs at C-4 and its role in protein binding remains elusive. Here, we determined the stereochemical configuration at carbon C-4 in the butenolide ring of spirolide- and gymnodimine-phycotoxins by comparison of measured 13C NMR shifts with values obtained in silico using force field, semiempirical and density functional theory methods. This comparison demonstrated that modeled data support S configuration at C-4 for all studied SPXs and GYMs, suggesting a biosynthetically conserved relative configuration at carbon C-4 among these toxins.

Ultra-performance hydrophilic interaction liquid chromatography tandem mass spectrometry system (UP-HILIC–MS/MS) was used in multi-toxin analysis of paralytic shellfish toxins (PSTs) and tetrodotoxins (TTXs) in sample matrices from bivalve molluscan species commercially produced for human consumption in Sweden. The method validation includes 17 toxins of which GTX6 and two TTX analogues, TTX and 4,9-anhydroTTX, were previously not analyzed together with hydrophilic PSTs. 11-deoxyTTX was monitored qualitatively with a non-certified reference standard. The performance of the method was evaluated for selectivity, repeatability, and linearity by analyzing spiked samples which generated linear calibration curves across the concentration ranges used (R2 > 0.99). The in-house reproducibility (RSD) was satisfactory including the LOD and LOQ for both PST and TTX toxins being far below their regulatory action limits. The major advantage of the method is that it allows direct confirmation of the toxin identity and specific toxin quantification using a derivatization-free approach. Unlike the PST-chemical methods used in routine regulatory monitoring until now for food control, the UP-HILIC-MS/MS approach enables the calibration set-up for each of the toxin analogs separately, thereby providing the essential flexibility and specificity in analysis of this challenging group of toxins. The method is suitable to implement in food monitoring for PSTs and TTXs in bivalves, and can serve as a fast and cost-efficient screening method. However, positive samples would, for regulatory reasons still need to be confirmed using the AOAC official method (2005.06).