Coffin Bay oysters are off the menu for the time being as an investigation begins into recent cases of people becoming sick due to the bacteria vibrio parahaemolyticus.
The Department of Primary Industries and Regions (PIRSA) has closed the oyster production areas of Coffin Bay as of Tuesday as a precautionary measure as part of an investigation into a recent rise in cases of vibrio parahaemolyticus, linked to eating raw oysters.
SA Health issued an alert about eating raw oysters on November 12 due to a rise in case numbers, with 45 cases reported since September, compared to zero in 2020 and eight in 2019.
PIRSA executive director of biosecurity Nathan Rhodes said the formal closure of the Coffin Bay Growing Area meant no oysters could leave the area, with the closure expected to remain until early next week.
He said the industry supported the closure and many growers had already voluntarily closed their harvesting operations.
"This precautionary closure has been put in place to provide us with the opportunity to trace back recent cases and enable further investigations," he said.
"PIRSA has consulted with industry, who have supported the closure, and has been working with SA Health on the public health impacts of the outbreak."
Vibrio parahaemolyticus is a bacteria found in marine, coastal and tidal areas which can cause gastroenteritis in humans and can be obtained through eating raw or undercooked shellfish or drinking contaminated water.
Symptoms usually occur within 24 hours of eating contaminated food and include watery diarrhoea, abdominal cramps, nausea, vomiting, headaches and fever.
In a statement the South Australian Oyster Growers Association says it is concerned with the recent cases and is working closely with SA Health and PIRSA on identifying the source of the outbreak.
The association said it was examining highly unusual environmental conditions which had not been seen before in SA, which had coincided with the outbreak.
Professor Ghil'ad Zuckermann from the University of Adelaide was one of the recent cases of vibrio parahaemolyticus and said he became sick after eating oysters during a visit to the Lower Eyre Peninsula.
On November 17 he said he was still feeling the effects more than 12 days after feeling sick and described it as "one of the most horrific diseases."
"You feel like you're going to faint and die, you feel like you're going to vomit your soul," he said.
Mr Zuckermann said he felt for the oyster growers in Coffin Bay whose businesses have come to a halt due to the outbreak, but was happy as well as he felt if older people had become sick with the bacteria, it would be an even worse result.
"I know personally older people who would've died if they'd gone through what I went through," he said.
The association is continuing to promote the best handling and storage options for pacific oysters, which includes storing raw unshucked pacific oysters at less than 10 degrees and shucked pacific oysters at less than five degrees to minimise the risk of infection.
It also encourages for pacific oysters to be discarded if they have been outside the fridge for more than two hours and if oysters have been frozen, they should be consumed immediately once thawed.
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