RESEARCH AND DEVELOPMENT OF AN ACCELERATED DETOXIFICATION SYSTEM FOR LIVE MARINE SHELLSFISH CONTAMINATED BY ALGAL PSP TOXINS
The production of live marine shellfish, and particularly of molluscs, is an important economic activity in the European Union : more than 1 200 000 tonnes in 1999 (FAO). The toxins represent two main problems : a health problem and an economical problem since the natural decontamination may take several weeks or months and therefore big economical losses. Shellfish are filter feeders, consume massive amounts of algae and so tend to concentrate contaminants from the water without harmful effects to themselves. Due to the way edible shellfish are eaten (slightly cooked or raw), algal toxins are not denatured. The health issues that are thus caused by algal toxins, of which PSP (Paralytic Shellfish Poisoning) is the most dangerous, must, of course be dealt with. Name
Effect if ingested
PSP : paralysing toxins Paralytic Shellfish Poisoning
Thematic
Paralysis occurs rapidly, with difficulty in breathing which can lead to death.
Alexandrium tamarense Copyright Ifremer
Location All over the world
Programme 1 Quality of Life and Management of Living Resources
ASP : amnesic toxins
Abdominal cramps, disorientation, Present in Europe and in serious cases loss of memory for several years and death Non-fatal gastro-enteritis occurs within 12 hours
All temperate zones
Diarrhoetic Shellfish Poisoning
Key Action 1 Health food and Nutrition
NSP : neurotoxins
Non-fatal gastro-enteritis
Oceania and the Americas
Amnesic Shellfish Poisoning DSP : Diarrhoetic toxins
Neurotoxic Shellfish Poisoning
Contacts coordinator of the project Mr. Frédéric Bailly
[email protected]
More than four different phycotoxins have been identified so far, with effects ranging from diarrhoea and vomiting known as diarrhoetic shellfish poisoning (or DSP), to paralysis known as paralytic shellfish poisoning (or PSP), which may lead to death. PSP is due to micro-algal blooms of Alexandrium spp. The most dangerous is PSP and the project is aimed at its detoxification.
Scientific Officer European Commission Isabelle de Froidmont-Göertz Objectives of the Project : isabelle.de-froidmont-goertz@ This project is based on an innovative principle of using optimal feeding rates of ec.europa.eu beneficial phytoplankton to accelerate the natural PSP decontamination processes of living shellfish. Website The objective of this project is to detoxify in 4 or 6 days from a level of 200µg/ 100g of http://shellfish.free.fr saxitoxin (the main PSP toxin) to below than the legal level of saxitoxin of 80 µg / 100g. The expected improvements will make the shellfish industry more efficient (higher quality, less waste), and therefore promote economic prosperity.
Strychnine 500 PSP saxitoxin 9 Cobra neurotoxin 0.3 0
100
200
300
400
g/kg/body weight
Relative fatal toxicity in the human body
500
600
Process : Shellfish are fed with specific micro algae, which reduce the time of detoxification. Water quality is restored through the use of a buffer tank incorporating the use of a mechanical filter (closed circuit). Moreover tanks are completed with disinfected sea water. Residual toxic cells are destroyed by sodium hypochloride injection. This innovative system allows acceleration of the detoxification of the Shellfish and also better control of detoxification process.
Shellfish accelerated detoxification system. Fluorimeter
Pump Mechanical Filter
Additional sea Water
Micro-algae
Buffer Tank
Traditional Tanks
Results
disinfection
:
The pre-industrial pilot constructed allows to process up to 150 kg of shellsfish. From the experimental trial performed it appears that detoxification trends observed at either 12, 16, or 20°C in oyster display detoxification times from 5.3 to 6.5 days, using either concentrated pastes or live cells of micro algea. From the results obtained on oyster it could be recommended to avoid temperatures as low as 12°C and also to stay within the range : 0.5 to 0.7 mg/l suspended matters during detoxification process since greater values might increase pseudo faeces production. Regarding experimental results with clams, safe levels (i;e
