Listeriosis, which has triggered a series of recalls of processed meat products, was the underlying or contributing cause in 11 deaths, up from 10, according to the Public Health Agency of Canada.

The death most recently linked to the food-borne illness was in Ontario and "likely occurred in the past several weeks," Dr. Mark Raizenne of the Public Health Agency of Canada said Sunday.

Since news of an outbreak emerged two weeks ago, Listeria monocytogenes has been the underlying or contributing cause in 11 deaths, including nine in Ontario, one in B.C. and one in Alberta, according to the agency.

Another six deaths are suspected and still under investigation, including four in Ontario, one in Quebec and one in Saskatchewan, the agency said.

A total of 33 cases across the country have been conclusively linked to the outbreak, up from the 31 cases reported in the agency's update Saturday. An additional 25 suspected cases are still under investigation, down from Saturday's update of 32.

Public health officials have warned the public to expect more confirmed or suspected cases to emerge because of the bacterium's long incubation period of up to 70 days.

The infection is of most concern to individuals who have weakened immune systems, the elderly, pregnant women and young children, the Public Health Agency of Canada said in newspaper advertisements published Saturday.

Last Saturday, as a precaution, Maple Leaf Foods expanded a recall of meat products to include everything that's processed at its Toronto plant after government lab tests conclusively linked the bacterium in the outbreak to some of the company's products. Several more products were added to the list of items Friday night.

Dr. Brian Evans, executive vice-president of the Canadian Food Inspection Agency, said while it may seem that the list of recalled products is growing, the additional recalls reflect the fact that several different products were made from the recalled meat.

"Many of our recalls relate to products such as sandwiches and pre-packaged meats carrying best-before dates that have now already expired," Evans said at a news conference Saturday afternoon.

"Nevertheless, in the public interest and in the interest of openness, we feel it is important that such info is visible."

On Saturday, the Canadian Food Inspection Agency warned people against eating certain roast beef sub and kaiser bun sandwiches by King Bean Wholesalers sold in B.C. stores in Surrey, New Westminster and Langley because they may be contaminated with the bacterium.

With files from the Canadian Press