Listeria Monocytogenes - NCTC 11994 & Salmonella typhimurium

How great is the risk for listeriosis ?

In the United States, an estimated 2,500 persons become seriously ill with listeriosis each year. Of these, 500 die. At increased risk are:

Pregnant women - They are about 20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy.

Newborns - 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 and The elderly

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

How does Listeria get into food ?

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. Unpasteurized (raw) milk or foods made from unpasteurized milk may contain the bacterium.

Listeria is killed by pasteurization and cooking; however, in certain ready-to-eat foods such as hot dogs and deli meats, contamination may occur after cooking but before packaging.