Marine biotoxins in Mediterranean seafood: Environmental occurrence and food safety concerns

Harmful Algal Blooms (HABs) are naturally occurring proliferations of microalgae that can negatively impact environmental, animal and human health, as well as societies. In the Mediterranean Sea, biotoxin-producing HABs events are becoming increasingly prevalent. This study addresses the gaps in consolidated data on biotoxin contamination levels in seafood by compiling and analyzing data from various sources. It provides a spatiotemporal overview of biotoxin occurrence in the Mediterranean Sea, identifying regional variations and data gaps, and assess human exposure to biotoxins. A comprehensive dataset was created that integrates information from 103 scientific publications and open access biotoxin monitoring databases. The analysis reveals that most publications focus on paralytic and diarrhetic shellfish toxins, which are predominantly found in bivalve molluscs, often exceeding Codex Alimentarius safety limits. Non-regulated toxins such as tetrodotoxin, pinnatoxin and palytoxins are also regularly found above recommended safety levels. Seafood consumption estimates, derived from the Aquatic Resource Trade in Species (ARTIS), Global Dietary database (GDD) and FAO regional capture, show that shellfish are a significant protein source for mediterranean countries, reaching 7.84 g/day/capita in Italy with up to 2.85 g/day/capita of locally sourced shellfish. This underscores potential human health risks in the absence of robust food safety monitoring systems. Data analysis reveals regional variations in toxin prevalence across Mediterranean sub-basins and highlights disparities in data availability, with toxin data available in only 11 out of the 23 Mediterranean countries. This work highlights the importance of international cooperation in data sharing through platforms such as the Harmful Algal Event Database (HAEDAT). It contributes to improving our understanding of contamination levels, essential for promoting food safety, food security, and sustainable economies in Mediterranean countries.