Melon association says fruit bought before Wednesday should be discarded or returned

This article is more than 2 years old

This article is more than 2 years old

Australians have been urged to throw out rockmelon amid a listeria outbreak in that has left two people dead in New South Wales.

Ten elderly people across Australia, including six from NSW, were diagnosed with the infection after consuming rockmelon and becoming ill between 17 January and 9 February, the NSW Food Authority said on Wednesday. The other cases were in Queensland and Victoria.

Two of the six who became ill in NSW subsequently died, a NSW Health spokeswoman confirmed.

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The outbreak has been linked to a rockmelon grower in Nericon in the NSW Riverina region, with the company voluntarily ceasing production after being notified of the contamination.

The Australian Melon Association has urged people to dispose of or return any rockmelons bought before Wednesday.

“Any current rockmelon bought before today, discard or take it back to the shop,” the association’s industry development manager, Dianne Fullelove, said on Wednesday. “Fruit on the shelf now is from farms that are not implicated.”

There have been 15 cases of listeria infection in Australia this year. Ten are being blamed on the contaminated rockmelon.

“Eating foods that contain listeria bacteria does not cause illness in most people, but in higher risk groups it can result in severe illness and even death so it’s vitally important these people take extra care at all times,” NSW Health’s communicable diseases director, Dr Vicky Sheppeard, said last week.

Listeria starts with flu-like symptoms such as fever, chills, muscle aches, nausea and sometimes diarrhoea but the symptoms can take a few days or weeks to appear after eating contaminated produce.

Prof Peter Collignon, an infectious diseases physician and microbiologist at the Canberra hospital, said on Thursday that people regularly ingested listeria and that for most, it was “water off a duck’s back” because the immune system could easily destroy it.

But the infection is particularly dangerous to people with compromised immune systems such as the elderly, pregnant women and people with underlying health conditions such as cancer, diabetes, heart and kidney disease.

Vulnerable people should avoid pre-cut melons. People at risk should consult their doctor as soon as possible if symptoms appear. Pregnant women often do not feel sick after being infected but the bacteria can cause harm to their baby, making precautions essential. The bacteria can’t be seen or tasted.

Collignon said melons usually became contaminated when exposed to manure, or to foliage such as hay, which could produce mould, creating conditions ripe for listeria to thrive.

“Rockmelon has a rough surface and the bacteria can get in the grooves and doesn’t come off easily, and spreads through the fruit during cutting,” he said. “The bacteria is also associated with dairy products like soft cheeses which is why pasteurisation is so important. But you can’t pasteurise a rockmelon.”

Listeria could reproduce at relatively low temperatures, he said, which meant refrigeration was not always adequate to prevent its growth.

