A woman who lived into her 90s in the Australian province of New South Wales (NSW) has become the sixth fatality in a rockmelon-caused listeriosis outbreak. With her death, the outbreak’s fatality rate is approaching 32 percent.
Rockmelons, or what we call cantaloupes in North America, are again being sold in Australia. NSW Health officials say melons now being sold are free of Listeria monocytogenes, and therefore safe to eat. But the danger remains for anyone who ate rockmelon suspected of contamination before it was all removed from the market in recalls.
From initial exposure to Listeria to the beginning of listeriosis symptoms can take as long as 70 days. The high fatality rate and the extended incubation period are unique to Listeria among foodborne pathogens.
Here’s how Australia’s listeriosis outbreak has played out:
Jan. 17 to Feb. 9 – This is the range of dates for the onset of illnesses for the first 10 cases of listeriosis in the Australian outbreak. Health officials mobilized in all states and territories, with illnesses found in NSW with 6, Queensland with 3, and Victoria with 1.
Feb. 23 – NSW Food Authority warns consumers “who are most vulnerable to Listeria infection such as older people, and people who have a weakened immune system due to illness or pregnancy” to avoid eating rockmelon after a recent spike in listeriosis cases in elderly people has been linked to the fruit.
In the same media release, the NSW Food Authority also says an unnamed rockmelon grower in the province was “voluntarily” ceasing production after its operation and the illnesses were linked. For those not in a vulnerable group, the NSW Food Authority promises rockmelon sold after Feb. 23 was safe to eat.
Feb. 28 – Food Standards Australia New Zeland (FSANZ) announces it is coordinating a trade recall of whole rockmelons following a spike in Listeria cases linked to rockmelons. “Eating foods that contain Listeria bacteria do not cause illnesses in most people, but in high-risk groups it can result in severe illness and even death,” FRANZ says in the recall notice.
It also says the NSW Food Authority is working with the grower to remove its rockmelon from the supply chain “so consumers can be assured that the fruit currently available on shelves are not implicated in this outbreak.”
Meanwhile, an Australian Melon Association spokeswoman says rockmelon produced by all other growers tested negative for Listeria and other types of melons are not implicated in the outbreak.
March 1 – The first two deaths are reported among the first 10 confirmed outbreak cases.
March 2 – Growers and retailers hold “crisis talks” as Australian public health officials urge consumers to throw away rockmelons over the ongoing Listeria outbreak. The situation is reminiscent of the deadly 2011 listeriosis outbreak in the United States. That outbreak was traced to Colorado brothers who used dirty water in their packing shed and ultimately sickened 147 people in 28 states, resulting in 35 deaths.
March 6 – Two more deaths are linked to the Australian outbreak, with the total number of confirmed cases rising to 17.
March 7 – Douglas Powell, a renown Kansas State University food safety expert living in Australia, questions the effectiveness of the country’s rockmelon recall, charging Australian’s reaction to the outbreak is “weak.” He points out that the limited information getting out is called “misinformation” by Australian’s growers.
“Sadly, the number of dead and sick will probably grow, because Listeria has an incubation period of two to six weeks,” Powell said. “The melon you ate five weeks ago could make you sick tomorrow. This is not misinformation, it’s biology.”
Meanwhile, the growers ask authorities to name the implicated grower.
March 13 – NSW Food Authority says Rombola Family Farms, one of Australia’s largest rockmelon growers and exporters, is the source of cantaloupes with the strain of Listeria monocytogenes causing the listeriosis outbreak.
It says it is working with Rombola and the broader rockmelon industry as it works to recover from the outbreak.
The outbreak includes 17 confirmed cases, including four deaths.
March 18 – The death of an elderly man becomes the outbreak’s fifth fatality. The number of confirmed cases reaches 19, including that of a pregnant woman who suffers a miscarriage.
March 20 – A woman in her 90s from New South Whales become sixth fatality.
May 4 – Seventy days after the recall: No further listeriosis cases should occur after this date, according to the timeline established by authorities in Australia.
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