About Listeria

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.

Listeria monocytogenes is found in soil and water. Vegetables can become contaminated from the soil or from manure used as fertilizer.
Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin such as meats and dairy products. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter.

Unlike most bacteria, Listeria can survive and sometimes grow on foods being stored in the refrigerator. In certain ready-to-eat foods such as hot dogs and deli meats, contamination may occur after cooking but before packaging. Moreover, foods that are contaminated with this bacterium look, smell and taste normal.

Who are at increased risk?
· Pregnant women are about 20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy.
· Newborns rather than the pregnant women themselves suffer the serious effects of infection in pregnancy.
· Persons with weakened immune systems
· Persons with cancer, diabetes, or kidney disease
· Persons with AIDS - They are almost 300 times more likely to get listeriosis than people with normal immune systems.
· Persons who take glucocorticosteroid medications
· The elderly

Healthy adults and children occasionally get infected with Listeria, but they rarely become seriously ill.

Additional precautions to reduce your risk:

· Do not eat hot dogs, luncheon meats, or deli meats, unless they are reheated until steaming hot.
· Avoid getting fluid from hot dog packages on other foods, utensils, and food preparation surfaces, and wash hands after handling hot dogs, luncheon meats, and deli meats.
· Do not eat soft cheeses such as feta, Brie, and Camembert, blue-veined cheeses, or Mexican-style cheeses such as queso blanco, queso fresco, and Panela, unless they have labels that clearly state they are made from pastuerized milk.
· Do not eat refrigerated pâtés or meat spreads. Canned or shelf-stable pâtés and meat spreads may be eaten.

After handling foods in the kitchen, especially raw foods such as meat and fish, thoroughly clean and sanitize all surfaces used for food preparation with a kitchen sanitizer (following the directions on the container) or use a bleach solution (5 ml household bleach to 750 ml of water), and rinse with water.
To avoid cross-contamination, clean all knives, cutting boards and utensils used with raw food before using them again.


Sources:
CDC (2008). Listeriosis. Retrieved from http://www.cdc.gov/nczved/dfbmd/disease_listing/listeriosis_gi.html
Health Canada (2006). Listeria and Food Safety Retrieved from http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/food-aliment/listeria-eng.php