Circannual Prevalence of tetrodotoxins in trumpet shells: Sea stars as a possible source of contamination and Implications for food safety

Tetrodotoxin (TTX) is a potent neurotoxin, first identified in fish from the Tetraodontidae family but also detected in marine invertebrates. A Human poisoning episode after consumption of trumpet shell Charonia lampas, likely caught off the Portuguese mainland southern coast – Algarve, together with the increasing reports of TTX in European waters, led the European Food Safety Authority (EFSA) to recommend maximum safe limits for Human consumption of shellfish meat. However, data on temporal and species incidence of TTX are lacking. In the present study, TTX and its analogues were analysed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) in trumpet shells and in one of their potential prey sources of TTX, the sea star Astropecten aranciacus. The estimated toxicity, based on a Toxicity Equivalency Factors approach, of non-edible trumpet shell tissues consistently surpassed EFSA limits (44 μg TTX equivalent (eq.) kg⁻¹) over the studied year. A correlation between TTX concentration and bottom seawater temperature suggests a possible role of this parameter in TTX uptake. TTX levels in edible trumpet shell tissues and all but one sea star individual were below quantification limits. However, several TTX analogues were quantified in the sea stars, resulting in estimated toxicities (monthly averages) ranging from 7 to 64 μg TTX eq kg⁻¹ in the digestive glands and from 0.3 to 27 μg TTX eq. kg⁻¹ in the stomachs. Therefore, the sea star is a possible TTX source for trumpet shells. Despite the absence of TTX in common edible parts of trumpet shells, whole-shell sales in markets pose a consumer risk, highlighting the need for TTX monitoring and public awareness programs to prevent poisoning.