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Marine Biotoxins in Shellfish

EU - The European Food Safety Authority (EFSA) has released an opinion on marine biotoxins in shellfish and contaminants within the food chain.

Azaspiracids (AZAs) are a group of shellfish toxins causing AZA poisoning (AZP) which is characterized by symptoms such as nausea, vomiting, diarrhoea and stomach cramps.

EFSA say that approximately 20 different analogues have been identified, of which AZA1, AZA2 and AZA3 are the most important ones based on occurrence and toxicity. AZAs can be found in various species of filter-feeding bivalve molluscs such as oysters, mussels, scallops, and clams.

Monitoring of AZAs in shellfish in Ireland has shown that mussels are the most affected species for this group of toxins. Only recently has the dinoflagellate that produces the AZA toxins been isolated. AZAs are nitrogen-containing polyether toxins comprising a unique spiral ring assembly, a heterocyclic amine (piperidine) and an aliphatic carboxylic acid moiety. AZAs in shellfish are not decomposed at temperatures relevant for cooking.

Only a few limited repeated-dose toxicity studies of longer duration (maximum duration 1 year) were available for AZA1. Pathological changes were observed in multiple organs; lungs, stomach, small intestine and liver. Occasionally lung tumours were observed. Because these tumours were only observed at doses causing severe toxicity, the CONTAM Panel considered this observation of limited relevance. No data on genotoxicity have been reported for AZAs.

The data on the chronic effects of AZAs in animals or humans were insufficient for a tolerable daily intake (TDI) to be established. In view of the acute toxicity of AZAs, the CONTAM Panel decided to establish an acute reference dose (ARfD) based on the available human data.

Further Reading

- You can view the full EFSA opinion by clicking here.

Ellen Hardy

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