How is Listeria spread?
The Listeria bacteria can be found in water and soil. Infected animals may also serve as sources. Unlike other organisms, Listeria can be spread by several different methods. Ingestion (food-borne transmission) of the organism, such as through unpasteurized milk, contaminated vegetables deli meats and cold cuts, soft-ripened cheese, milk, undercooked chicken, uncooked hot dogs, shellfish, and coleslaw made from contaminated cabbage. In newborn infections, the organism may be transmitted from mother to fetus in utero, or directly to the fetus at the time of birth. Direct contact with the organism can cause lesions on the skin. Ingestion of as few as 1,000 cells of Listeria bacteria can result in illness. After ingestion of food contaminated with Listeria, incubation periods for infection are in the range of 3 to 70 days, usually 4 to 21 days. Five days to three weeks after ingestion, Listeria has access to all body areas and may involve the central nervous system, heart, eyes, or other
