Yerseke, June 25 2016 – The Dutch mussel season will kick off as planned on June 29th, with two shellfish-production areas in the Easterscheld under temporary closure orders from the Dutch Food and Consumer Product Safety Authority (NVWA).The mussel industry will take precautionary measures to ensure complete food safety of mussels entering the market.
The NVWA closed the two areas after the neurotoxin Tetrodotoxin (TTX) was discovered in shellfish samples from these areas. The NVWA carries out weekly sampling for all shellfish production areas in The Netherlands to guaranty the safety of the shellfish. Once new samples show that TTX is no longer present, the areas will be re-opened by the NVWA.
The areas concerned, Easterscheld East and Easterscheld North, are not main production areas for bottom-grown mussels. However, the re-watering plots (also called ‘wet warehouses’) for the trading companies are situated in these areas. The industry is therefore taking precautionary measures, and will carry out additional sampling to ensure the food safety of all mussels delivered to restaurants and retailers.
The new season for Dutch bottom-grown mussels starts on Wednesday June 29 and July and August are traditionally important for the mussel industry. “Mussels are eaten in abundance during the summer, mainly on restaurant terraces along the Belgian coast and in the larger Belgian cities. They are particularly appropriate for outside eating. We are happy to announce that the supplyof mussels will not be affected. The industry are taking their own measures, and are working with the NVWA to ensure all food safety precautions are in place. We all have a shared interest in this,” said Wouter van Zandbrink, chairman of the Organisation of Mussel Traders.
The mussel industry has a long standing and comprehensive monitoring programme for toxic algae in place. These algae can develop naturally in the sea water during the warmer months and the NVWA takes weekly samples of water and shellfish to analyse for toxins. This year, TTX has been added to the monitoring program. When samples show high values of toxins, the NVWA takes preventative measures by closing the concerned production areas, until new samples show that the situation has reverted to normal and the area is safe to reopen. This early warning and response-system guarantees the safety of produce that reaches the mussel trading companies, and ultimately the marketplace.
Tetrodotoxin (TTX) is a neurotoxin, that occurs worldwide in nature. It is one of the most abundant toxins used by animals to protect themselves from predators. Certain species of fish (like pufferfish), the blue-ringed octopus, and certain species of amphibians and reptiles (like toads) actively produce the toxin as a form of protection. Shellfish do not produce the toxin themselves, but can become contaminated through filter-feeding. Due to the high level of filtration, shellfish can also rid themselves quickly of the toxin.
At present, the source of TTX in Dutch waters is unknown, and work is in hand to understand the development of the toxin-build up and decrease in shellfish. Possible sources of TTX are Nemertea, algae or bacteria (Vibrio). Both Vibrio and Nemertea are present in the Easterscheld. but the algae associated with TTX are a less likely source in The Netherlands, according to IMARES, the Dutch Institute for Marine Resources & Ecosystem Studies. Neurotoxins are chemical compounds that can affect the neuro system.