Canadian public-health officials reevaluated the death toll linked to contaminated cold cuts and said it rose from 4 to 12 on Monday, while Maple Leaf Foods expanded a nationwide food recall.

The increase in the number of deaths caused by listeriosis, in addition to 26 confirmed cases of the infection, indicate the fact that the illness is an intensifying disaster for Maple Leaf Foods Inc., a leading Canadian food processing company.

Listeriosis is a serious infection caused by eating food tainted with a bacterium called Listeria monocytogenes. It can have hazardous effects on senior citizens, newborn infants, pregnant women and people with weakened immune systems. Muscle aches, nausea, diarrhea, loss of balance and headaches count among the symptoms.

Among the 26 cases reported in Canada, most of them occurred in Ontario, Mark Raizenne, director-general for the Canadian Food Inspection Agency, said Tuesday at a press conference held in Ottawa.

In addition to this, other 29 suspected cases are subject of an investigation aimed to establish whether they were related to the listeria outbreak or not, according to Agriculture Minister Gerry Ritz.

Raizenne added that the number of confirmed cases, as well as suspected ones might soon increase.

The strain of listeria was tracked at a Toronto plant run by Maple Leaf Foods.

“It’s clear that the confidence in Maple Leaf and our brand has been shaken and I feel very badly about that,” Michael H. McCain, the company’s president and chief executive, told the media on Sunday.