Oysters now safe, mussels not
23 January 2019 | Fishing
A little less than two weeks ago, a public warning was issued after oyster and mussel samples from the production area tested positive for diarrhetic shellfish poisoning (DSP), making them unsafe for consumption.
Yesterday the ministry said it is safe again to eat oysters from the area, which tested negative after repeated testing and “may therefore be harvested for direct human consumption”.
However, the latest results for the mussel samples collected from the area, which were submitted for sampling and testing to the Namibian Standards Institution (NSI), as guided by the national shellfish sanitation programme, indicate that the presence of DSP is still above the maximum permissible levels.
The ministry therefore said the production area remains closed for the harvesting of mussels for direct human consumption, depuration or relaying.
DSP is one of the four recognised symptom types of shellfish poisoning.
The syndrome manifests itself as intense diarrhoea and severe abdominal pains. Nausea and vomiting may sometimes also occur.
DSP and its symptoms usually set in within 30 minutes after ingesting infected shellfish and last for about a day.
The causative poison is okadaic acid, which inhibits intestinal cellular de-phosphorylation.
This causes the cells to become very permeable to water and causes profuse, intense diarrhoea with a high risk of dehydration.
As no life-threatening symptoms generally emerge from this, no fatalities from DSP have ever been recorded.