ReviewRelevance and challenges in monitoring marine biotoxins in non-bivalve vectors

- Contamination with biotoxins is surveyed in monitoring programmes for bivalve species.
- EU Directives also apply to echinoderms, tunicates and marine gastropods.
- These organisms present diverse physiological traits from bivalves, mainly in feeding habits.
- Published reports on toxins in these vectors were reviewed.
- High risk species are highlighted and their surveillance requirements discussed.

Seafood poisoning outbreaks can be caused by marine biotoxins which are naturally produced by harmful algal blooms. To minimize the risk of acute intoxications due to consumption of contaminated seafood a proper monitoring program must be in place. In recent decades several directives have been laid down by the European Commission to regulate known toxins, reassess their regulatory limits and update their reference detection methods. However, a revision of the seafood organisms that can act as toxin vectors has not been carried out. The control system has been designed based on physiological specificities of live bivalve mollusks. Although the prescribed controls in EC regulation 854/2004 apply to echinoderms, tunicates and marine gastropods, several difficulties are posed to a cost-effective monitoring program for these quite diverse and non-analogous groups of seafood organisms. Echinoderms, tunicates and marine gastropods are frequently secondary target species for toxins surveillance. In this study, the potential of non-bivalve organisms as toxin vectors and their threat for public health is evaluated based on their feeding behavior (i.e. filter-feeders, herbivores, predators), growth and metabolic rates, motile capacity and dynamics of toxin accumulation/elimination. A summary of previous reports on toxin accumulation and human incidents is presented to highlight the seafood species of higher risk to consumers, including crustaceans that are not listed in the EU directives for toxins monitoring and should be strongly considered as potent vectors of biotoxins to humans. Finally, the challenges in terms of sampling efforts and analytical determination for the regular surveillance of biotoxins in non-bivalve vectors are discussed.