We run a biotoxin monitoring programme to ensure that shellfish are not placed on the market, when toxins are present.
This involves monitoring the presence of naturally occurring phytoplankton toxins in Irish shellfish and analysing seawater for the presence of toxin producing phytoplankton. The programme is designed to detect toxicity in shellfish growing areas before shellfish are harvested to prevent the placement of toxic shellfish on the market.
We are the National Reference Laboratory (NRL) for marine biotoxins and operate within the the EU network of NRLs which is lead by the EU Reference Lab in Vigo. The objective of the NRL is to facilitate a high level of expertise, knowledge and communication on the topic throughout Ireland.
The NRL also provides the scientific framework required to implement appropriate sampling and analytical monitoring programmes.
Three groups of toxins are established in the (EU) No 853/2004 and the monitoring of shellfish is necessary to comply with the regulation before they can be placed on the market:
1. Ammesic Shellfish Poisoning (the ASP toxins, Domoic acids)
2. Paralytic Shellfish Poisoning (the PSP toxin; Saxitoxin group)
3. Lipophilic Marine Toxins including;
- Diarrheic shellfish poisoning (the DSP toxin okadaic acid and dinophysistoxins)
- Azaspiracids (the AZA toxins)
- Pectonotoxins (the PTX toxins)
- Yessotoxins (the YTX toxins)
We have developed methods using the most modern chemical analytical tests as approved by the official EU method.
Regulation EC No 853/2004 governs the total amount of marine biotoxins that may be present in shellfish for the protection of consumers. These are:
- 800 microgram per kilogram of the algal toxins that cause paralysis (Paralytic Shellfish Poison - PSP).
- 20 milligram per kilogram of domoic acids which cause amnesia (Amnesic Shellfish Poison - ASP).
- 160 microgram okadaic acid equivalent per kilogram expressed as a sum of okadaic acid, dinophysis toxins and pectenotosins.
- 1 milligram yessotoxin equivalent per kilogram and
- 160 microgram azaspiracid equivalent per kilogram expressed as the sum of azaspiracid-1, 2 and 3.
Regulation EC No 2074/2005 stipulates which test methods may be used to detect marine biotoxins.
Toxicity can occur at any time during the year and the periods of closure can vary considerably from year to year. The main toxicity that affects Irish shellfish are from a group of phytoplankton called the dinoflagellates. While most of these are beneficial, a small number of species produce toxins, usually in the summer, although we have had winter episodes from both known and unknown sources.
The complex toxin profile of Irish shellfish checks year round vigilance on the part of the industry and monitoring agencies, and regular testing should be integrated into the producers routine quality control procedures.
Proceedings from the past nine Irish Shellfish Safety Scientific Workshops are now available to download in our Publications section under Marine Environment & Health Series section.
For more information contact Joe Silke