The Australian oyster industry has a clean bill of health for the two most common food-borne viruses that cause gastroenteritis.
The first comprehensive survey for Norovirus and Hepatitis A virus in water taken from Australia’s commercial oyster farms was done by the South Australian Research Development Institute (SARDI).
Molecular microbiologist at SARDI’s Food Safety and Innovation laboratories Dr Valeria Torok said 300 samples were taken from all Australian oyster production areas and tested using an international standard.
“Out of the 300 samples we tested for Norovirus and Hepatitis A virus, we didn’t detect any positive samples,” Dr Torok said.
“Enteric viruses, which cause gastroenteritis, these are spread human to human but they can contaminate food.
“And in foods that are not cooked or processed it can actually lead to illness.”
Dr Torok said there was no baseline data for food-borne viruses in Australian oysters prior to this survey.
She said the national prevalence of both viruses was found to be less than 2 per cent.
Dr Torok said that compared very well to other places where similar surveys had been done.
“It has been done in several other countries where the prevalence has been reported to be from 40 per cent up to 76 per cent,” she said.
The industry is really quite efficient in their shellfish management and we produce safe shellfish.Dr Valeria Torok
“The issue is really when there is a high population around an area that has an oyster lease.
“There is potential for human waste to contaminate those growing waters.
“We generally haven’t had an issue here in Australia, but we’ve never really known what the baseline prevalence has been.”
Dr Torok said the Australian research was funded by the Fisheries Research and Development Corporation and Oysters Australia.
She said the results could be used to oppose any move towards mandatory testing of shellfish.
“It’s really come out of EU [European Union] suggestions that they may be working towards mandatory testing of oysters for enteric viruses,” Dr Torok said.
“It’s a fantastic result, saying that the industry is really quite efficient in their shellfish management and we produce safe shellfish.
“And it can also be used for market access into other countries.”