Marine biotoxins

Marine biotoxins can occasionally contaminate some species of seafood. There is Europe-wide legislation to limit their levels in seafood that is placed on the market.

The table below outlines limits that apply to bivalve molluscs, echinoderms, tunicates and gastropods placed on the market. The values refer to samples measured in 'the whole body or any part edible separately'.

Seafood Maximum permitted level

Paralytic shellfish poisoning (PSP)


Amnesic shellfish poisoning (ASP)

20mg of domoic acid/kg

Okadaic acid, dinophysistoxins and pectenotoxins

160µg of okadaic acid equivalents/kg


3.75mg yessotoxin equivalent/kg


160µg azaspiracid equivalents/kg

For more information, see the Commission Regulation 853/2004 as amended (see in particular Chapter V, Section VII in Annex III of the Regulation). The methods used for determining the toxins are described in Annex III of Regulation 2074/2005.

UK guidance and information

The FSA's Shellfish Monitoring page has information on regulation and monitoring of the shellfish harvesting industry.

FSA Scotland have produced a document entitled Managing Shellfish Toxin Risks, which is a toolkit that harvesters and processors can use to assess risks associated with algal toxins in bivalve molluscs. The guide encourages food business operators to use commercial rapid test kits (where available) to measure toxin levels in the batch they are handling rather than rely on official monitoring. Areas where wild fisheries for bivalve molluscs take place may not have historical data on the presence of algal toxins, and harvesters are encouraged to use commercial rapid test kits (where available) to measure toxin levels even where the batch being handled is destined for an approved processing or dispatch centre. The FSA Scotland letter covering the above guidance can be found here.

FSA Scotland in collaboration with Cefas have devised a quicker method for reporting Paralytic Shellfish Poisoning (PSP) measurements by producing 'semi quantitative' results. Semi-quantitative results from samples containing toxins below the alert level of 400 µg/kg will be reported immediately and within 24hrs of receipt of the sample. Samples at or above 400 µg/kg will proceed to full testing. The reporting table has been amended to accommodate the new results; you can see an example here. This is a significant improvement and should result in those placing products on the market making more confident decisions in a timely manner.

Food Standards Scotland reports its resuts of biotoxin monitoring here.
England and Wales report here; Northern Ireland report biotoxin results here.