A NSW man has been confirmed as the third fatality in Australia's largest outbreak of listeria.

The death of the 68-year-old man late last month was confirmed by Victoria's acting chief health officer as being linked to the outbreak at Jindi, one of the nation's biggest cheese companies.

The outbreak, which has been traced to the company's factory in Gippsland, Victoria, has been linked to the deaths of an 84-year-old Victorian man and a 44-year-old Tasmanian man.

Twenty-six cases have been identified so far, including a NSW woman who had a miscarriage.

Victoria's Department of Health maintains it acted promptly to contain the outbreak, which came to the attention of authorities in mid-December and led to the recall of more than 100 cheese products, but it has warned there could be more cases and further fatalities.

''I'm confident the intervention that has been put in place with terrific co-operation from Jindi is absolutely appropriate and is the best possible,'' said the acting chief health officer, Michael Ackland. ''Unfortunately because of the 70-day incubation period for listeria, there will almost certainly be people who have consumed cheese prior to the recall who may still get sick … that could go on for another couple of months.''

Listeria can cause illness or death in the elderly and people with low immune systems, and miscarriage and neonatal infection in pregnant women, but many healthy people show no symptoms.

The confirmation of a third death comes as Australian food retailers, including Coles and Woolworths, prepare to restock shelves with Jindi products later this week.

Jindi Cheese recalled batches of brie and camembert on December 19 after the first cases were identified. On January 18, the company extended the recall to all batches it manufactured up to January 6, including other brands such as Wattle Valley and Coles Finest.

Dr Ackland said the listeria outbreak was the largest the nation had suffered and one of the most complex. He described the process of tracking the outbreak to Jindi as ''an important piece of investigative work'', which involved obtaining food histories from victims and intelligence from OzFoodNet, the federal food diseases surveillance unit, as well as bacterial DNA tests to determine the strain of listeria.

Since the national recall, the same listeria strain has been found in victim samples, some recalled Jindi cheese lines and at the factory.

Dr Ackland said he had full confidence the Jindi products going back on shop shelves this week and manufactured on or after January 7 were ''absolutely as safe as can be for human consumption''.

On January 7, Jindi's French-owned parent company, Lactalis - which bought the gourmet cheese maker from Menora Foods in November for an estimated $20 million - voluntarily committed to a quality assurance program that ''significantly cranks up'' its existing food safety standards and has satisfied Victoria's chief health officer.

Dr Ackland added that there was ''no suggestion whatsoever'' that Jindi had not been complying with Dairy Food Safety Victoria's stringent food safety regulations.

''The problem with listeria is it is ubiquitous - it's all over the place and from time to time it does pop up, and it loves soft cheese,'' he said.

Investigations are continuing to determine how the listeria came to resist the usual safety protocols and contaminate the Jindi products.

Jindi's chief executive, Franck Beaurain, has not returned telephone calls from Fairfax Media for more than a week.