More than 60 people have fallen ill with salmonella thought to be linked to pre-mixed salads purchased in Victoria.
The Federal Department of Health said on Saturday it was closely monitoring the outbreak in the state after a meeting on Friday between health and foodborne disease authorities on the emerging situation.
It said the number of people affected by the outbreak had jumped overnight.
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"The meeting noted that Victorian health authorities had reported 54 cases of Salmonella Anatum infection linked to the consumption of mixed salad products," it said in a statement.
"This figure has, of today, increased to 62 cases of Salmonella Anatum infection although food histories are yet to be conducted to establish any links to the mixed salad products."
It said other states and territories were examining up to 30 possible cases of Salmonella Anatum infection.
"Whether these cases are linked to the outbreak strain in Victoria, or coincidental to it, requires confirmation by the ongoing investigation including laboratory testing," the department added.
It said Victorian health authorities were leading the investigation into the source of the salmonella outbreak.
Authorities launched a probe after becoming aware of almost 30 cases of the rare infection on Tuesday.
According to Fairfax Media, the department is interviewing patients to determine whether they have eaten recalled products, which were sold at Coles, Woolworths, Bi-Lo and other grocers as Coles 4 Leaf Mix, Woolworths salad mix, SupaSalad Supamix and Wash N Toss salad mix.
Senior lecturer in the Food Science and Technology Group from the University of New South Wales, Dr Jian Zhao, said it was increasingly common for people to become infected through vegetables.
"Salmonella is common -- it is one of, if not the most, commonly implicated pathogens involved in foodborne outbreaks,” Dr Zhao told The Huffington Post Australia.