Smoked salmon, believed to be from Tasmania, has been identified as the likely source of listeriosis which has killed two people interstate - one in NSW and another in Victoria.
In a statement Australia's chief medical officer said the department of health was investigating three cases of listeria infection, including a non-fatal case in Queensland, linked to smoked salmon.
All cases occurred in people aged over 70, with existing underlying health conditions.
Primary Industries and Water Minister Guy Barnett said evidence suggested the salmon linked to the listeria cases had come from Tasmania, but would not go into details about its source.
"I won't go into those details. That is obviously a very important matter," he said.
"What I will say is the Department of Primary Industries has investigated the matter.
"There has been no breach of the law, in terms of food safety and the production of salmon in Tasmania."
A Tasmanian Health Service spokesman said there had been no listeria cases reported in Tasmania this year.
There have been 27 cases of listeriosis reported Australia-wide in 2019 and three in Tasmania since 2016.
A spokesman for Tasmanian-based salmon farming company Tassal said it was not aware of any evidence linking its products to the two listeria deaths.
"Tassal products have not been deemed unsafe, nor has it breached the Food Standards Code," the spokesman said.
"Tassal manufacturing protocols and policies comply with and often exceed all required standards set by the Australian federal and state government authorities and the Australian New Zealand Food Standards Code.
"These are supported by the regulator, the Tasmanian DPIPWE as well as multiple independent third party audits."
In other news:
- Launceston councillor Andrea Dawkins in support of Northern pill testing trial
- World champion Ariarne Titmus en route to becoming Tasmania's greatest ever athlete
- Supreme Court at Burnie holds trial of man charged with sex crimes against six child complainants
- Federal Court case involving unpaid rates from two Tasmanian airports to conclude
A Huon Aquaculture spokeswoman said its cold smoked salmon products were recently tested by health authorities.
"No positive results for listeria were recorded nor was any breach of Australian food safety standards noted," the spokeswoman said.
"Our factory is independently audited multiple times per year to comply with our certification requirements resulting in Huon not having a product recall in the past eight years.
"It is also important to remember that 50 per cent of smoked salmon consumed in Australia is imported product."
Tasmania's salmon industry is estimated to be worth more than $704 million.
Primary Industries, Parks, Water and Environment's produce safety chief inspector Chris Lyall said the department had conducted a review of the food safety programs of Tasmania's three salmon producers.
"The three major producers all have appropriate food safety programs in place specific to the seafood industry. This includes listeria management," he said.
"DPIPWE has undertaken inspections of the plants of the major producers and the department has not found any evidence of non-compliance with the Food Standards Code.
"The department is continuing to work with the department of health and Tasmanian producers to ensure best practice."
Petuna Aquaculture said its cold smoked salmon had been recently tested and returned no positive results for listeria, and no breaches of any national food safety standards.
What is listeria?
Listeriosis is an illness usually caused by eating food contaminated by the bacterium listeria monocytogenes.
The bacteria are widely distributed in the environment and can grow in food at refrigeration temperatures.
Most people who are exposed to listeria will only develop mild symptoms, though illness can be severe in those most at-risk.
Those at increased risk of illness include pregnant women and their unborn babies, newborn babies, the elderly, and people of all ages with immune systems weakened by illness or medication.
Listeria infection starts with flu-like symptoms such as fever, chills, muscle aches, nausea, and sometimes diarrhoea.
People can start experiencing symptoms within a few days, but symptoms can take a number of weeks to appear after eating a contaminated product.
Foods that have a higher risk of listeria contamination include:
- chilled seafood such as raw oysters, sashimi and sushi, smoked ready-to-eat seafood and cooked ready-to-eat prawns
- cold meats from delicatessen counters and sandwich bars, and packaged, sliced ready-to-eat meats
- cold cooked ready-to-eat chicken (whole, portions, or diced)
- pre-prepared or pre-packaged fruit or vegetable salads, including those from buffets and salad bars
- soft, semi-soft and surface-ripened cheeses such as brie, camembert, ricotta, blue and feta
- refrigerated paté or meat spreads
- soft serve ice cream