Calming the Listeria Hysteria: FAQs about LM and Food Safety

We’ve seen Listeria and its scientific name, listeria monocytogenes, cropping up lately in the news.  But what is it exactly?  Who does it affect?  And how can we avoid it?  To help answer some of your most pressing questions about Listeria, check out the following FAQs.

What is listeria monocytogenes?

Listeria monocytogenes (pronounced lis-TIR-ee-ya mon-o-si-TAH-gin-eez), is a type of bacteria found everywhere in soil and ground water and on plants.  Listeria can cause an illness called Listeriosis.

Who’s at risk for Listeriosis?

Most people are not at increased risk for Listeriosis. However, those with weakened immune systems such as children, the elderly and especially pregnant women, are considered more susceptible to Listeriosis.

Where is Listeria commonly found and under what conditions?

Listeria monocytogenes is found in soil and water. Animals can carry it without appearing ill.  Unless treated during the production phase, it can contaminate foods of animal origin, such as meats and dairy products.  It 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.  Unpasteurized (raw) milk and cheeses and other foods made from unpasteurized milk are particularly likely to contain Listeria.

Foods most commonly associated with Listeria and support its growth include:

  • Hot dogs
  • Luncheon meats
  • Bologna and other deli meats
  • Refrigerated pate
  • Meat spread from a meat counter
  • Smoked seafood found in the refrigerated section
  • Raw (unpasteurized) milk
  • Salads made in the store
  • Soft cheese such as Feta, queso blanco, queso fresco, Brie, Camembert cheeses, blue-veined cheeses, and Panela unless it is labeled as made with pasteurized milk

Dried foods do not support the growth of Listeria

Source:  USDA Fact Sheet on Listeriosis

What can consumers do to reduce the risk of listeriosis?

  • Thoroughly cook raw food from animal sources, such as beef, pork, or poultry to a safe internal temperature. Visit the USDA website for a list of recommended temperatures for meat and poultry.
  • Cook hot dogs, luncheon meats or deli meats until they are steaming hot.
  • Do not drink raw (unpasteurized) milk, and do not eat foods that have unpasteurized milk in them.
  • Keep uncooked meats and poultry separate from vegetables and from cooked foods and ready-to-eat foods.
  • Rinse raw vegetables thoroughly under running tap water before eating.
  • Wash hands, knives, countertops, and cutting boards after handling and preparing uncooked foods.
  • Consume perishable and ready-to-eat foods as soon as possible.
  • Be aware that Listeria monocytogenes can grow in foods in the refrigerator. Use an appliance thermometer, such as a refrigerator thermometer, to check the temperature inside your refrigerator. The refrigerator should be 40°F or lower and the freezer 0°F or lower.
  • In addition to following the above recommendations, those at-risk individuals should avoid eating high risk foods such as soft cheeses and pâté.


Consumer’s Guide to Food Safety

Listeriosis and Pregnancy:  What is Your Risk?

USDA Fact Sheet on Listeriosis

CDC:  Frequently Asked Questions about Listeriosis