What Is Listeria?

Find out how listeriosis, a gastrointestinal illness with a high mortality rate, can get passed via a variety of foods from cooked eggs to deli meats.

Keystone - News & Insights

May 24, 2017

Listeria monocytogenes is a pathogen that causes listeriosis, a severe gastrointestinal illness. Unlike most other foodborne pathogens, listeria can grow at proper refrigeration temperatures. Listeriosis is a rare disease with a high mortality rate. People at highest risk include the elderly, pregnant women, young children and the immunosuppressed. In the U.S., 43% of food poisoning deaths are attributed to listeriosis.

Listeria can enter a restaurant via food contaminated:

  • in produce-growing environments
  • during processing
  • during handling and preparation

Food particularly sensitive to listeria are:

  • raw or unpasteurized dairy products
  • raw meat and poultry
  • deli salads
  • deli meats
  • fresh soft cheese (non-hot packed)
  • cooked meat, poultry and seafood (including smoked)
  • cooked eggs

Contributing factors associated with listeriosis risk include:

  • amount and frequency of consumption of a listeria-sensitive food
  • frequency and extent of contamination of a food with listeria
  • temperature and duration of refrigerated/chilled food storage
  • whether food can support growth of listeria


Read more about Listeria at the CDC.