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Contamination & Pathogens

Listeria monocytogenes

A bacterium that causes listeriosis, a serious infection particularly dangerous for pregnant women, elderly people, and those with weakened immune systems.

What It Means

Listeria monocytogenes is a species of pathogenic bacteria that causes listeriosis, a serious and sometimes fatal infection. Unlike most foodborne pathogens, Listeria can grow at refrigerator temperatures (as low as 35 degrees Fahrenheit), which makes it particularly dangerous in ready-to-eat foods that are consumed without further cooking. Listeriosis is relatively rare compared to other foodborne illnesses — the CDC estimates about 1,600 cases per year in the U.S. — but it has one of the highest mortality rates of any foodborne pathogen, with approximately 260 deaths annually. Pregnant women are about 10 times more likely to get listeriosis than other healthy adults, and the infection can cause miscarriage, stillbirth, premature delivery, or life-threatening infection in newborns. Listeria contamination is a common trigger for Class I food recalls because of the severity of the illness it causes. Foods frequently associated with Listeria contamination include deli meats, soft cheeses made with unpasteurized milk, smoked seafood, raw sprouts, cantaloupe, and ready-to-eat salads. The bacterium can persist in food processing environments, particularly in areas with moisture, making it a significant challenge for food manufacturers. Thorough cooking kills Listeria, but many high-risk foods are consumed without heating.

Related Terms

Frequently Asked Questions

What does Listeria monocytogenes mean?

A bacterium that causes listeriosis, a serious infection particularly dangerous for pregnant women, elderly people, and those with weakened immune systems.

Why is Listeria monocytogenes important for food safety?

Listeria monocytogenes is a species of pathogenic bacteria that causes listeriosis, a serious and sometimes fatal infection. Unlike most foodborne pathogens, Listeria can grow at refrigerator temperatures (as low as 35 degrees Fahrenheit), which makes it particularly dangerous in ready-to-eat foods ...