Smoked salmon has been identified as the likely source of listeriosis, which has killed two people - 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 infections, including a third non-fatal case in Queensland.
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."
All cases occurred in people aged over 70, with existing underlying health conditions.
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.
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