Tests have established a link between a deadly nationwide bacterial outbreak and recalled meat products from Maple Leaf Foods, Canadian public health officials said Saturday night.

"Results of genetic testing from three samples of the products recalled by Maple Leaf Foods show that two tested positive for the outbreak strain of listeria," the Public Health Agency of Canada said in a statement.

It said test results for the third product were a close match to the outbreak strain, but showed a slight variance.

"While these results are highly significant, and indicate that the investigation is on the right path, the investigation is not complete," the agency said. "Test results on additional food samples expected next week will advance the investigation further."

The results are "good news" because they confirm that health officials are looking in the right places for the cause of the outbreak, officials of the Canadian Food Inspection Agency said at an evening news conference in Ottawa.

"We're very confident that we're on the right path," said Garfield Balsan, a food safety and recall specialist with CFIA.

The products being tested came from Maple Leaf's plant in Toronto.

Maple Leaf expands product recall

Maple Leaf responded to the test results by announcing it was recalling more products as a precaution.

"The company has made the decision to expand its product recall to include all production from the Bartor Road facility as a further precautionary measure, notwithstanding the fact that there is no evidence of listeria contamination in product beyond the production lines originally under investigation," CEO Michael McCain said in a release.

McCain said he expects the additional recall to be implemented swiftly. He said a list of specific products and codes will be published by Sunday morning on the company website.

"Tragically, our products have been linked to illness and loss of life. To those people who are ill, and to the families who have lost loved ones, I offer my deepest and sincerest sympathies", McCain said. "Words cannot begin to express our sadness for their pain.

"This week our best efforts delivering the highest quality, safe food have failed us. For that we are deeply sorry," he said. "We know this has shaken consumer confidence in us. Our actions will continue to be guided by putting their interest first."

CFIA says product recall 'going very well'

Balsan said the product recall "is proceeding and it's going very well" but is a huge task because the products are very popular and are sold throughout Canada.

"This is a very large recall right across the country involving thousands of accounts," he said. CFIA staff have already visited thousands of places, many of them health-care facilities and old-age homes.

"We will ensure this plant is thoroughly cleaned up and that any product produced in that facility is safe to consume," Balsan said.

The listeria outbreak has been linked to four deaths out of a total of 21 confirmed cases.

Three of the deaths were in Ontario. Listeria was also found in the body of a man who died in a Vancouver Island hospital in late July.

Of the 21 confirmed cases, 16 are in Ontario, three are in British Columbia, one is in Saskatchewan and one is in Quebec.

An additional 30 suspected cases are being probed to confirm if they are related to the outbreak: 14 from Ontario, eight in Quebec, four from Alberta, and two each from Saskatchewan and British Columbia.