what causes listeria

Listeria is caused by a bacterium called Listeria monocytogenes, which is commonly found in soil, water, sewage, decaying vegetation, and animals. It can contaminate a wide range of foods, especially refrigerated ready-to-eat foods such as cold deli meats, unpasteurized dairy products, soft cheeses, smoked and cured fish, pre-prepared sandwiches and salads, and pre-cut fruits. The bacteria can survive and even grow at refrigerator temperatures, making it difficult to control in food storage. People typically contract listeriosis, the illness caused by Listeria, by consuming food contaminated with this bacterium. It can also be transmitted through close contact with farm animals or contaminated environments. Listeria passes through the digestive tract and can invade cells, leading to infection, especially in pregnant women, infants, elderly, and immunocompromised individuals.