The European Commission asked EFSA to assess the current EU limits which exist for six different types of toxins in shellfish, known as marine biotoxins[1] and the testing methods established in EU legislation. Marine biotoxins are poisonous substances produced by different algae that can accumulate in shellfish.

This EFSA opinion brings together the conclusions of six earlier risk assessments on marine biotoxins. For each type of toxin, the Panel established the amount which can be consumed within a 24-hour period without any appreciable health risk (the acute reference dose). These were then compared with shellfish consumption and occurrence data from a number of EU countries in order to assess the EU limits.

Using available consumption data, the experts identified 400g as a realistic estimate of a large portion of shellfish and used this in assessing current permitted levels of the toxins. Based on these calculations, however, people eating a smaller portion of shellfish contaminated with toxins from the okadaic acid, azaspiracid, saxitoxin or domoic acid groups could also experience ill effects, such as diarrhoea and vomiting.

The Panel concluded that the mouse bioassay, an official test used for analysis of most of these toxins[2] in shellfish, could not be sufficiently sensitive to detect specific toxins or to determine whether the levels of some of the toxins are at or below current EU limits. The Panel made recommendations for future work on alternative methods.

EFSA’s scientific advice on this issue will help inform any appropriate follow-up action to be taken by the Commission. Later this year, EFSA is due to publish a further series of opinions on marine biotoxins for which no EU limits have so far been set.