Here's what you should know about Listeria contaminations in Canada

The latest Listeria contamination involves some plant-based beverages in Canada. However, from pre-packaged salads to six-layer bean dips to mushrooms, this isn't the first time food or drink products have been recalled due to the bacteria.

Listeria monocytogenes, widely referred to as Listeria, can be found in soil, vegetation, sewage and water, as well as in the feces of both animals and humans, food safety organizations say.

People who eat foods contaminated with Listeria may carry the bacteria and not develop the listeriosis illness. But in other cases, it can be deadly. 

"Once it gets in the system, it's a bad bug to have," said Dr. Michael Rieder, a professor in the department of pediatrics, medicine and pharmacology at Western University.

More than a week after the Canadian Food Inspection Agency (CFIA) recalled some oat, almond and coconut drinks from the Silk and Great Value brands, two people in Ontario have died from listeriosis.

In total, Ontario, Quebec and Nova Scotia have 12 confirmed cases related to this current outbreak, according to the Public Health Agency of Canada (PHAC). 

In recent years, about 134 cases of invasive listeriosis have been reported annually in Canada, reports PHAC. Here's what you need to know.

In the last few months, several products have been recalled in Canada over possible Listeria contamination. 

Most recently, enoki mushrooms, certain meat and vegetable products, as well as salad kits and bean dip, were recalled. None of these incidents led to confirmed cases or deaths in Canada, but products had to be tossed due to the risk. 

Each province and territory tracks listeriosis cases, while PHAC issues public health notices when there's an active outbreak that's under investigation. PHAC also publicly tracks past outbreaks.

"Each time you handle a food and process a food, [you] increase the chance of bacteria getting into it," said Rieder. 

It's thought that "ultra-processed foods" are at a greater risk of having some type of bacteria in them compared to less processed ones, he said. 

Keith Warriner, a food scientist at Guelph University in Ontario, says that outbreaks usually arise from a lapse in the plant's sanitation practices. 

"If you don't do sanitation correctly, you don't monitor it, it doesn't matter how much you process it, it's going to get contaminated," he said.