Listeria monocytogenes Infection (cont.)
Listeriosis is a disease caused by infection with a gram-positive, rod-shaped
bacterium called Listeria monocytogenes.
- Listeria monocytogenes is ubiquitous, and it is usually found in soil, water,
and decaying vegetation. Many farm animals and other domestic and wild animals
can harbor the bacterium. Though many of these animals may be asymptomatic
carriers of the bacterium, they can serve as a source to contaminate the foods
produced from them, such as meat and dairy products. Listeria monocytogenes may
also enter food-processing factories and contaminate food contact surfaces and
non-food contact surfaces (for example, floors or drains).
- Listeria monocytogenes may contaminate various foods and dairy
products, for example, raw vegetables and fruits, uncooked meats, packaged and
processed meats (for example, hot dogs or deli meats), smoked seafood, soft cheeses, and
unpasteurized milk/dairy products.
- Listeriosis is most often a food-borne illness that is transmitted to
humans after they ingest foods or liquids contaminated with Listeria monocytogenes.
- Human-to-human transmission occurs when an infected pregnant mother
transmits the infection to her fetus/newborn via the placenta or during
- In the United States, 2,500 cases of listeriosis are reported annually,
with about 500 fatalities reported per year.
- In 2011, contaminated cantaloupes from a Colorado farm caused 146 cases of
listeriosis with 32 fatalities, making it the deadliest food-borne illness
outbreak in the United States since the early 1900s.