Silk plant-based beverages are returning to grocery stores following a deadly Listeria outbreak linked to a number of recalled products.

Danone Canada told CTV News Toronto that while the third-party production facility in Pickering, Ont. where the recalled products were made remains closed during an ongoing Canadian Food Inspection Agency (CFIA) investigation, production has resumed elsewhere.

“We have progressively ramped up production of our Silk refrigerated products in other facilities and products impacted by the recall are gradually coming back to shelves,” a spokesperson said in an email on Wednesday.

The news comes after the Public Health Agency of Canada (PHAC) announced Monday that a third person had died in connection with the Silk and Great Value brand plant-based milk recall. It's unclear if the affected Great Value brand products have returned to shelves.

Ontario’s Ministry of Health confirmed to CTV News Toronto on Wednesday that the third person who died was from the province. The other two deaths linked to the outbreak were also from Ontario, CTV News Toronto previously reported.

The products, including almond, oat, cashew and coconut-based milk substitutes, were recalled on July 8. Since then, PHAC has confirmed 20 cases of listeriosis, including 13 in Ontario, five in Quebec and one each in Nova Scotia and Alberta. Fifteen of those individuals were hospitalized as a result of their infection.

The people who became sick, the CFIA said, developed symptoms between August 2023 and early July 2024 and most of them were adults above the age of 50. At least 17 of the infections started in June and July, CFIA data shows.

Officials said more illnesses linked to the outbreak may continue to be reported because the illness reporting period is between nine and 29 days.

The CFIA said the affected products were distributed across the country.

Symptoms of listeriosis may start as early as three days after eating contaminated food, but could take up to 70 days after exposure to develop. The CFIA said symptoms include fever, nausea, cramps, diarrhea, vomiting, headache, constipation and muscle aches. However, in severe cases, the bacteria can spread to the nervous system and cause symptoms like stiff neck, confusion, headache and loss of balance.

People with weakened immune systems and adults over the age of 60 are particularly at risk of developing severe listeriosis symptoms after exposure. Pregnant women and their unborn or newborn babies are also at a heightened risk.

If you believe you have any of the recalled products, a full list of which can be found here, the CFIA says throw them out or return them to the retailer. If you think you are experiencing symptoms of a Listeria infection, contact your doctor.

Why does it take so long for listeriosis symptoms to develop?

Keith Warriner is a professor of food science at the University of Guelph and says the reason listeriosis symptoms can sometimes be delayed is due to the pathogen’s ability to avoid detection by the body’s immune system.

“The Listeria are held within a vacuole to protect against being attacked by the immune system,” the former chef told CTV News Toronto in an email. “Eventually it can enter the bloodstream, nervous system or placenta which causes listeriosis.”

Warriner said that Listeria is especially resilient as it can survive in an open field as well as in the gastrointestinal tract of an animal.

As for how the pathogen may have found its way inside the Pickering plant, Warriner listed a number of possible sources, including the nuts used in the dairy-alternative beverages, the air coming into the facility, workers’ shoes, rodents or insects.

“Once within the facility, then Listeria could grow on almond milk and form biofilms that are difficult to remove. Listeria has been known to persist in processing facilities for years,” he said.