Agriculture Minister Barnaby Joyce has urged Aussie consumers to buy local produce after a spate of hepatitis A cases understood to be caused by contaminated frozen berries, spread to Western Australia.

In South Australia, health authorities notified parents of students at nine primary schools that their children may have consumed potentially contaminated Nanna’s berries.

Meanwhile, Victoria’s Ballarat High School year seven students have been informed they ate Hepatitis A linked berries after making smoothies during a cooking class.

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The WA case is believed to be the first detection of hepatitis A allegedly caused by the Nanna’s brand of frozen berries, a Department of Health spokesman said.

The berries are believed to have been the source of at least 15 other confirmed cases across Australia so far.

One childcare centre, understood to be the McKay Children’s Centre at Penola in SA’s south-east, feared smoothies reportedly made with a frozen mixed berry pack were served to children as part of their afternoon snack.

McKay Children’s Centre at Penola may have served frozen berries contaminated with hepatitis A to children. Photo: ABC

Letters have been sent to parents of the children notifying them of the possible risk.

The centre’s director declined to comment on the situation.

Chief education officer Jayne Johnston said parents would be understandably concerned to get the letter.

“But I would like to emphasise that SA Health advises that the risk is considered to be quite low and the product recall was being undertaken as a precaution,” she said.

“I also don’t know how the berries were used, it may have just been with one class, it may have been put into muffins sold at the canteen so it’s very hard to get a judgment, but all parents are being notified if the school has told us the berries might have been used.”

Barnaby: ‘buy local’

Mr Joyce told the Nine Network on Wednesday there was a way to avoid the disease all together.

“That is, to make sure you eat Australian product,” Mr Joyce said.

“I want to make sure I do everything in my power to say to people your safest food is your domestic food. That is why you pay a premium for Australian product. It is clean, green and healthy.”

Federal Agriculture Minister Barnaby Joyce.

Australians are being urged not to consume Nanna’s Raspberries 1kg packs, Nanna’s Frozen Mixed Berries 1kg packs, and 300g and 500g packs of Creative Gourmet Mixed Berries.

Communicable Disease Control director Paul Armstrong said there was no need for people who had eaten the products and remained well to see their doctor for testing or vaccination.

Symptoms of hepatitis A can start two to seven weeks after exposure to an infectious person or after eating contaminated food.

Early symptoms are fever, nausea, loss of appetite and abdominal discomfort.

After several days jaundice can develop, with yellowing of the whites of the eyes and skin, dark urine and pale stools, sometimes accompanied by diarrhoea.

Dr Armstrong said anyone who experience symptoms should see their doctor, especially if they had eaten the berries.

The latest case came as the Federal Department of Agriculture confirms it has written to Chinese authorities demanding assurances that measures are in place to prevent further contamination of frozen berries.

In a statement, the Department of Agriculture said it was engaging Chinese government authorities through Australian embassy staff in Beijing, seeking assurances about the safety of further shipments of frozen berries.

Poor hygiene among workers and contaminated water supplies were thought to be behind the contamination.

But Mr Joyce said country-of-origin labelling and consuming locally produced food were the most effective ways to ensure food safety.

“As this issue has come to light, we have made sure that we’re on our front foot and trying to deal with it,” he said.

“I think we have to strengthen our labelling laws and we currently have a review before us which I believe needs to be stronger than what it actually came into my office (as),” he said.

– with ABC, AAP