The Public Health Agency of Canada says seven people have been hospitalized in a Listeria outbreak affecting five provinces.
The agency says there were three cases in Ontario and one each in Quebec, New Brunswick, Prince Edward Island, and Newfoundland and Labrador.
The people, most of them women and with an average age of 81, became sick between September 2015 and early January 2016 and one of them has died, but it has not been determined if Listeria contributed to the death.
The agency says the source of the outbreak has not been confirmed, however prepackaged leafy greens, salad blends, and salad kits are being investigated.
It says the risk to Canadians from this outbreak is low, but given that Listeria can cause severe illness to some high-risk groups, consumers are being asked to review and follow safe food handling practices in an effort to prevent illnesses.
Listeria is a type of bacteria that can be found in food, soil, plants, sewage and other places in nature, and eating food with Listeria on it can cause a serious disease, called listeriosis. People can get listeriosis by eating meat, fish, dairy products, plants or vegetables contaminated with Listeria.
Those who are at highest risk of serious illness, according to Health Canada, include pregnant women and unborn or newborn children, adults 65 and over, and people with weakened immune systems.
High-risk individuals should follow safe food handling practices and avoid high risk food items such as uncooked meat and vegetables, unpasteurized milk and cheeses, ready-to-eat meats such as hot dogs and deli meats, and refrigerated smoked seafood and fish.
Foods that are contaminated with Listeria may look, smell and taste normal. Unlike most bacteria, Listeria can survive and sometimes grow on refrigerated foods but can be killed by cooking food properly.
The mild symptoms of listeriosis may include fever, muscle aches, nausea, or diarrhea, while severe symptoms can include headache, poor co-ordination, seizures or neck stiffness.
In the milder form of the disease, symptoms can start the day after eating a contaminated product, but for the more serious form of the disease, the incubation period generally averages about 21 days and can be up to 70 days.
Listeriosis can be treated with antibiotics, but the agency says early diagnosis is key, especially for people in high-risk groups.