Toxicity Screening of a Gambierdiscus australes Strain from the Western Mediterranean Sea and Identification of a Novel Maitotoxin Analogue

Dinoflagellate species of the genera Gambierdiscus and Fukuyoa are known to produce ciguatera poisoning-associated toxic compounds, such as ciguatoxins, or other toxins, such as maitotoxins. However, many species and strains remain poorly characterized in areas where they were recently identified, such as the western Mediterranean Sea. In previous studies carried out by our research group, a G. australes strain from the Balearic Islands (Mediterranean Sea) presenting MTX-like activity was characterized by LC-MS/MS and LC-HRMS detecting 44-methyl gambierone and gambieric acids C and D. However, MTX1, which is typically found in some G. australes strains from the Pacific Ocean, was not detected. Therefore, this study focuses on the identification of the compound responsible for the MTX-like toxicity in this strain. The G. australes strain was characterized not only using LC-MS instruments but also N2a-guided HPLC fractionation. Following this approach, several toxic compounds were identified in three fractions by LC-MS/MS and HRMS. A novel MTX analogue, named MTX5, was identified in the most toxic fraction, and 44-methyl gambierone and gambieric acids C and D contributed to the toxicity observed in other fractions of this strain. Thus, G. australes from the Mediterranean Sea produces MTX5 instead of MTX1 in contrast to some strains of the same species from the Pacific Ocean. No CTX precursors were detected, reinforcing the complexity of the identification of CTXs precursors in these regions.

Occurrence of cyclic imines in European commercial seafood and consumers risk assessment

Cyclic imines constitute a quite recently discovered group of marine biotoxins that act on neural receptors and that bioaccumulate in seafood. They are grouped together due to the imino group functioning as their common pharmacore, responsible for acute neurotoxicity in mice. Cyclic imines (CIs) have not been linked yet to human poisoning and are not regulated in the European Union (EU), although the European Food Safety Authority (EFSA) requires more data to perform conclusive risk assessment for consumers. Several commercial samples of bivalves including raw and processed samples from eight countries (Italy, Portugal, Slovenia, Spain, Ireland, Norway, The Netherlands and Denmark) were obtained over 2 years. Emerging cyclic imine concentrations in all the samples were analysed on a LC-3200QTRAP and LC-HRMS QExactive mass spectrometer. In shellfish, two CIs, pinnatoxin G (PnTX-G) and 13-desmethylspirolide C (SPX-1) were found at low concentrations (0.1-12µg/kg PnTX-G and 26-66µg/kg SPX-1), while gymnodimines and pteriatoxins were not detected in commercial (raw and processed) samples. In summary, SPX-1 (n: 47) and PnTX-G (n: 96) were detected in 9.4% and 4.2% of the samples, respectively, at concentrations higher than the limit of quantification (LOQ), and in 7.3% and 31.2% of the samples at concentrations lower than the LOQ (25µg/kg for SPX-1 and 3µg/kg for PnTX-G), respectively. For the detected cyclic imines, the average exposure and the 95th percentile were calculated. The results obtained indicate that it is unlikely that a potential health risk exists through the seafood diet for CIs in the EU. However, further information about CIs is necessary in order to perform a conclusive risk assessment.

Insights from an international stakeholder consultation to identify informational needs related to seafood safety

Food safety assessment and communication have a strong importance in reducing human health risks related to food consumption. The research carried out within the ECsafeSEAFOOD project aims to assess seafood safety issues, mainly related to non-regulated priority environmental contaminants, and to evaluate their impact on public health. In order to make the research results accessible and exploitable, and to respond to actual stakeholders' demands, a consultation with international stakeholders was performed by means of a survey. The focus was on policy and decision makers, food producers and processors, and agencies (i.e. EU and National or Regional agencies related to Food Safety or Public Health) and consumer organisations. The survey considered questions related to: seafood safety assessment and mitigation strategies, availability of data, such as the level of information on different contaminants, and communication among different stakeholder groups. Furthermore, stakeholders were asked to give their opinion on how they believe consumers perceive risks associated with environmental contaminants. The survey was distributed to 531 key stakeholders and 91 responses were received from stakeholders from 30 EU and non-EU countries. The main results show that communication between different groups of stakeholders needs to be improved and that there is a deficit of information and data in the field of seafood safety. This pertains mainly to the transfer of contaminants between the environment and seafood, and to the diversity of environmental contaminants such as plastic additives, algal toxins and hormones. On-line tools were perceived to be the most useful communication channel.