Listeria monocytogenes is a bacterium
commonly found in soil, stream water, sewage, plants, and food. Each bacterium is gram-positive and rod-shaped. Listeria are known to be
the bacteria responsible for listeriosis, a rare but potentially lethal food-borne infection: the case fatality
rate for those with a severe form of infection may approach 25%.
They are incredibly hardy and able to grow in temperatures ranging from 4°C (39°F), the temperature of a refrigerator, to 37°C (99°F),
the body's internal temperature. Furthermore, listerosis's deadliness can be partially attributed to the infection's ability to spread to
the nervous system and cause meningitis. Finally, Listeria has a particularly high occurrence rate in newborns because of its ability to infect
the fetus by penetrating the endothelial layer of the placenta. Vegetables can become contaminated from the soil, and animals can also be carriers.
Listeria has been found in uncooked meats, uncooked vegetables, unpasteurized milk, foods made from unpasteurized milk, and processed foods.
Listeria is killed by pasteurization and cooking. There is a chance that contamination may occur in ready-to-eat foods such as hot dogs and deli
meats because contamination may occur after cooking and before packaging.
Abbreviated from Wikipedia.