Foodborne illness occurs when a person consumes food contaminated with pathogenic bacteria, viruses or parasites. This condition is often called "food poisoning". Many cases of foodborne illness go unreported because their symptoms often resemble flu symptoms. The most common symptoms of foodborne illness may include stomach cramps, nausea, vomiting, diarrhea and fever.
Listeria monocytogenes (commonly called Listeria) is a type of bacterium often found in food and elsewhere in nature. It can cause a rare but serious disease called listeriosis, especially among pregnant women, the elderly or individuals with a weakened immune system. In serious cases it can lead to brain infection and even death.
Listeria is widespread in the environment - found in soil, vegetation, water, sewage, silage and in the faeces of humans and animals. Animals and humans can carry the bacterium without knowing it.
Plants and vegetables can become contaminated with Listeria from the soil, water and manure-based fertilizers. Farm animals that appear healthy may also carry Listeria and contaminate foods such as meats and dairy products.
Unlike most bacteria, Listeria can survive and sometimes grow on foods being stored in the refrigerator. Moreover, foods that are contaminated with this bacterium look, smell and taste normal. Listeria can be killed by proper cooking procedures.
Listeria is more likely to cause death than other bacteria that cause food poisoning. In fact, 20 to 30 percent of foodborne listeriosis infections in high-risk individuals may be fatal. However, it should be noted that listeriosis is a relatively rare disease in Canada.
Many people may be carriers of Listeria, but few will actually develop listeriosis. Those who do will likely become ill from eating food contaminated with the bacteria, often seen as an outbreak of what people would call "food poisoning". Symptoms may start suddenly and include:
In some instances, these symptoms may be followed by meningitis encephalitis (an infection of the brain or its surrounding tissues) and/or septicemia (blood poisoning), either of which can result in death.
The mild form of foodborne listeriosis usually begins about one day after eating heavily contaminated food. For the more serious form of the disease, the incubation period is generally much longer - up to 70 days after exposure.
Those who are at the highest risk of serious illness include:
The disease can be effectively treated with antibiotics, but early diagnosis can be critical to the success of the treatment, especially for those at high risk. At the moment, there is no vaccine to prevent listeriosis.
You can minimize your chances of contracting listeriosis (as well as other foodborne illnesses) by following these steps.
In addition, the recommendations below should be followed by high-risk individuals:
Foods to Avoid: | Safer alternatives: |
---|---|
Hot dogs, especially straight from the package without further heating. The fluid within hot dog packages may contain more Listeria than the hot dogs. Avoid spreading fluid from packages onto other foods, cutting boards, utensils, dishes and food preparation surfaces. Wash your hands after handling hot dogs. |
Hot dogs reheated until steaming hot |
Non-dried deli-meats | Dried and salted deli-meats such as salami and pepperoni, as they generally do not support the growth of Listeria. In addition, you can reduce your risk by reheating deli-meats until steaming hot. |
Soft and semi-soft cheeses such as feta, Brie, Camembert and blue-veined cheese if they are made from unpasteurized milk | Pasteurized milk and milk products including cheeses made from pasteurized milk |
Refrigerated pâté and meat spreads | Canned or shelf-stable pâté and meat spreads |
Refrigerated smoked seafood and fish | Cooked refrigerated smoked seafood and fish. Canned or shelf-stable smoked seafood and fish. |
Raw or undercooked meat, poultry and fish | Thoroughly cooked meat, poultry and fish |
Health Canada develops food safety standards and policies to help minimize
the risk of foodborne illnesses. The Canadian Food Inspection Agency (CFIA)
carries out inspection of the food industry to ensure that it meets its food
safety responsibilities. Health Canada, in collaboration with the CFIA, has developed a
The Public Health Agency of Canada (PHAC), the CFIA, and Health Canada work with public health officials, and provincial ministries of health to confirm the source of the listeria related illnesses when an outbreak is suspected. When cases occur in multiple provinces, federal officials lead the epidemiological investigation. In addition, they provide reference laboratory services, conduct food safety investigations and recall actions.
For more information on foodborne illness and safe food handling practices, visit the Canadian Food Inspection Agency website at www.inspection.gc.ca