How does someone get listeriosis?
People get listeriosis by eating food contaminated with Listeria monocytogenes 1. Babies can be born with listeriosis if their mothers eat contaminated food during pregnancy. However, healthy people may consume contaminated foods without becoming ill. People at risk can prevent listeriosis by avoiding certain high-risk foods and by handling and storing food properly.
Listeria monocytogenes is commonly found in soil and water. Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin, such as meats and dairy products.
When Listeria bacteria get into a food processing factory, they can live there for years, sometimes contaminating food products 4. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in foods that become contaminated after cooking or processing, such as soft cheeses, processed meats such as hot dogs and deli meat (both products in factory-sealed packages and products sold at deli counters), and smoked seafood. Unpasteurized (raw) milk and cheeses and other foods made from unpasteurized milk are particularly likely to contain the bacterium.
Listeria is killed by pasteurization and cooking; however, in some ready-to-eat foods, such as hot dogs and deli meats, contamination may occur after factory cooking but before packaging. Unlike most bacteria, Listeria can grow and multiply in some foods in the refrigerator.
- Schlech WF, 3rd, Lavigne PM, Bortolussi RA, Allen AC, Haldane EV, Wort AJ, Hightower AW, Johnson SE, King SH, Nicholls ES, Broome CV. Epidemic listeriosis--evidence for transmission by food. The New England journal of medicine. 1983;308(4):203-6.
- Painter J & Slutsker L. Listeriosis in humans. In: E. T. Ryser & E. H. Marth., editor. Listeria, Listeriosis and Food Safety 3rd ed Boca Raton, Florida: Taylor and Francis Group; 2007. p. 85-110.
- Schuchat A, Lizano C, Broome CV, Swaminathan B, Kim C, Winn K. Outbreak of neonatal listeriosis associated with mineral oil. Pediatr Infect Dis J. 1991;10(3):183-9.
- Tompkin RB. Control of Listeria monocytogenes in the food-processing environment. Journal of food protection. 2002;65(4):709-25.