It's Your Health
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It's Your Health
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.
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 90 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.
|Type of Food||Food to Avoid||Safer Alternative|
|Hot dogs||Hot dogs straight from the package without further heating.||Hot dogs thoroughly cooked to a safe internal temperature. The middle of the hot dog should be steaming hot or 74°C (165°F)|
|Tip: To help prevent foodborne illness, avoid spreading fluid from packages onto other food, cutting boards, utensils, dishes and food preparation surfaces. Wash your hands after handling hot dogs.|
|Deli meats||Non-dried deli meats, such as bologna, roast beef and turkey breast.||Dried and salted deli meats such as salami and pepperoni.
Non-dried deli meats heated throughout to steaming hot.
|Egg and egg products||Raw or lightly cooked egg or egg products, including salad dressings, cookie dough or cake batter sauces, and drinks such as homemade eggnog.||Egg dishes thoroughly cooked to a safe internal temperature. Eggs should be cooked until the yolk is firm.
Homemade eggnog must be heated to 71°C (160°F).
|Tip: Pasteurized egg products can be used when making uncooked food that calls for raw eggs|
|Meat and poultry||Raw or undercooked meat or poultry, such as steak tartare.||Meat and poultry cooked to a safe internal temperature. (refer to the Internal Cooking Temperatures Chart)|
|Tip: To help prevent foodborne illness, remember to use a digital food thermometer to check the internal temperature.|
|Seafood||Raw seafood, such as sushi.
Raw oysters, clams, and mussels.
Refrigerated, smoked seafood.
|Seafood cooked to a safe internal temperature of 74°C (165°F).
Cook until the shell has opened.
Smoked seafood in cans that do not require refrigeration until after opening.
|Tip: Refrigerated smoked seafood can be eaten safely when fully cooked to a safe internal temperature, such as in a casserole.|
|Dairy products||Raw or unpasteurized dairy products, including soft and semi-soft cheese, such as Brie, Camembert and blue-veined cheese.||Pasteurized dairy products, hard cheeses such as Colby, Cheddar, Swiss, and Parmesan.|
|Sprouts||Raw sprouts such as alfalfa, clover, radish, and mung beans.||Thoroughly cooked sprouts.|
|Pâtés and meat spreads||Refrigerated pâtés and meat spreads.||Pâtés and meat spreads sold in cans or those that do not require refrigeration until after opening.|
|Fruit juice and cider||Unpasteurized fruit juice and cider.||Unpasteurized fruit juice and cider brought to a rolling boil and cooled.|
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.
Health Canada develops food safety standards and policies to help minimize the risk of foodborne illnesses. Canadian Food Inspection Agency(CFIA) oversees the food industry to ensure that it meets its food safety responsibilities. Health Canada, in collaboration with the (CFIA), has developed a policy on Listeria monocytogenes in Ready-to-Eat Foods which includes inspection and corrective measures.
Health Canada also briefs the medical community, public health officials, the food industry and the public on matters related to listeriosis. As a founding member of the Canadian Partners for Consumer Food Safety Education, Health Canada also participates in public awareness campaigns about safe food practices.
You can also call toll free at 1-866-225-0709 or TTY at 1-800-267-1245*
Original: October 2005
©Her Majesty the Queen in Right of Canada, represented by the Minister of Health, 2005
Update: March 2010