All cases have been hospitalized, and one person has died, however it is not clear if Listeria contributed to the cause of death.
The Public Health Agency of Canada (PHAC) said infections have been reported in five provinces: Ontario (3), Quebec (1), New Brunswick (1), Prince Edward Island (1), and Newfoundland and Labrador (1).
It said the risk is low, but given that Listeria can cause severe illness to some high-risk groups, Canadians should review and follow proper safe food handling practices in an effort to prevent illnesses.
Individuals became sick between September and early January 2016. The majority of cases (71%) are female, with an average age of 81 years.
In the milder form of the disease, symptoms can start the following day after eating a contaminated product. For the more serious form of the disease, the incubation period is generally much longer; on average about 21 days, but can be up to 70 days after exposure.
Link to leafy greens and salad
The source has not been confirmed but pre-packaged leafy greens, salad blends and salad kits are food items being investigated.
Dr Eric Hoskins, Ontario minister of health and long term care and Dr David Williams, acting chief medical officer of health, said they are working with Public Health Ontario and provincial partners to investigate the Listeria monocytogenes infections.
“Some of these cases are also part of a federally led national investigation," they said.
“To date, the source of these Listeriosis infections has not been confirmed. We will update the public as new information from the ongoing investigation becomes available.
“We will continue to work closely with our partners and will provide additional updates as more information becomes available.”
Blue Bell update
Meanwhile, Blue Bell Ice Cream has entered phase five of its market re-entry plan.
The firm also gave an update on progress with its enhanced testing in production facilities.
It has identified suspected areas where bacteria may be present but has not found Listeria monocytogenes.
“We have identified locations where suspected Listeria species may be present in our facility, and we continue to extensively clean and sanitize those areas and make additional enhancements to the facility and our procedures based on the environmental test results," said the firm.
“To confirm that our robust environmental program is effective, and that our “seek and destroy” goals are being achieved, we expect to periodically find microbiological indications in our facilities.
“The entire purpose of our enhanced environmental testing is to identify locations where bacteria could be found in our facility in order to properly clean and sanitize the surface and prevent contamination.
“We have tested and will continue to test every batch of ice cream produced. No products produced have tested positive. No products are shipped to stores until tests confirm they are safe.”