Written by Mònica Campàs, IRTA, Monica.Campas@irta.cat
Tetrodotoxin (TTX) is a potent neurotoxin responsible for food poisoning incidents, mainly related with the consumption of pufferfish (Tetraodontidae) in tropical or subtropical regions of Asia and the Pacific Islands. Since 2007, TTX has been found in some shellfish from European countries such as the United Kingdom, Greece, the Netherlands, Spain and Italy, though concentrations have been low so far.
Currently there is no maximum permissible level of TTXs in shellfish in Europe, but the European Food Safety Authority (EFSA) affirms that concentrations below 44 μg of TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, do not result in adverse effects in humans.
Researchers from the Institute of Agrifood Research and Technology, Queen’s University Belfast, and Biorex Food Diagnostics have recently developed a method to quickly screen for the presence of tetrodotoxin in shellfish. The method utilises an antibody which specifically recognises tetrodotoxin and several of its analogues. Unlike conventional immunoassays, performed on plates, this method exploits magnetic beads as antigen immobilisation supports. The use of magnetic beads reduces the shellfish matrix effects, thus allowing the detection of tetrodotoxin at concentrations as low as 1 μg/kg in oysters and razor clams, and 3.3 μg/kg in mussels – levels well below the EFSA guidance threshold.
The analysis, which can be performed in less than two hours, has been proved to be useful to guarantee shellfish safety and protect human health. It is also applicable to managing shellfish production areas, and in research studies.
SEAFOODTOMORROW researchers have published a scientific article around the results, which is included in the Special Issue “Eco-innovative sustainable solutions for the seafood industry: Findings & Challenges” from Food and Chemical Toxicology, available here
A fast magnetic bead-based colorimetric immunoassay for the detection of tetrodotoxins in shellfish © Mònica Campàs