Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: An in vitro digestion approach
This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood. ; The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under the ECsafeSEAFOOD project (grant agreement n° 311820) and through the European Regional Development Fund. IRTA members acknowledge support from CERCA Programme/Generalitat de Catalunya. L.R. acknowledges a scholarship from the ECsafeSEAFOOD project. Ana C. Braga has a Doctoral Grant (PD/BD/113484/2015) from the Portuguese Science and Technology Foundation (FCT), whereas Antonio Marques and Pedro R. Costa are supported through the FCT Investigator program (IF). Lagocephalus sceleratus was kindly provided by Andrés Izquierdo-Muñoz from Centro de Investigación Marina de Santa Pola (CIMA) (Spain).