The shellfish are currently tested daily by RIKILT and IMARES investigates the source of the contamination in the Oosterschelde and the possibilities of purifying mussels and oysters. Other tested shellfish samples taken from shellfish production areas such as the Wadden Sea and other parts of the Oosterschelde are free of toxins, making them safe for consumption.
What is TTX?
Tetrodotoxin (TTX) is a neurotoxin that occurs naturally in (sub) tropical seas. It is highly likely to be produced by a bacterium, and can end up (directly or indirectly) via soil, water or algae in shellfish. Even in very small quantities TTX can all affect the human nervous system, therefore it is regulated by the government. TTX is best known because it can be in pufferfish. In Japan, where they like to eat these fish are annually dozens of people sick after eating puffer fish.
TTX Origin Unclear
It is still unclear how TTX ended up in the Oosterschelde or how it originated. The cause could be in bacteria commonly found in the marine environment and therefore also in the Oosterschelde. However, it is a complex system, wherein the interaction between water, algae, sediment organisms and plays an important role. At this time, it is not yet clear whether TTX also occurs in other organisms.
RIKILT Currently Testing Daily Mussels and Oysters
The Dutch Food Safety Authority (NVWA) and the shellfish industry let the mussels and oysters currently on daily basis test by RIKILT. Within a day it is known whether the shellfish are infected with TTX. If that is the case, they can not be harvested and sold. Analyses are performed with sophisticated chemical detection methods. Furthermore RIKILT involved as National Reference Laboratory for marine biotoxins as an expert to the government.
IMARES and RIKILT Investigate the Source of TTX
The shellfish sector has IMARES and RIKILT commissioned to investigate the source of TTX in the Oosterschelde. Then there any measures can be taken by the shellfish industry. The researchers hope to find out within two months, which is the source of the infection or at least to obtain good indications.
IMARES Investigates Purification Mussels and Oysters
The toxin comes from the natural functioning of the ecosystem in the shellfish. Once the source is no longer available, the toxin will also through the natural system disappear from the seafood again. It is commissioned by the shellfish industry is currently investigating detoxification of shellfish. For this purpose, purification methods that are also used may be used by the mussel sector in practice. This can be possibly used the natural cleansing power of mussels.
Food Safe Mussels and Oysters
No mussels and oysters are fished out of closed areas. Mussels and oysters that consumers in the supermarket, fish shop, fish stall and restaurants to eat, so can be eaten safely.