Listeria and Food
Outbreaks in the 1990s were primarily linked to deli meats and hot dogs. Now, Listeria outbreaks are mainly caused by soft Mexican-style cheeses, like queso fresco, and other cheeses that were either made from unpasteurized milk or contaminated during cheese-making. Some outbreaks have also been caused by foods that people may not think of as risky for Listeria, like celery, sprouts, and cantaloupe.
Learn about some of the foods where Listeria has been known to hide:
Soft cheeses made with unpasteurized milk are estimated to be 50 to 160 times more likely to cause Listeria infection than when they are made with pasteurized milk. Although pasteurization of milk kills Listeria, contamination can occur in milk products made from pasteurized milk if they are produced under unsanitary conditions.
A. Soft cheeses generally are smooth and easy to spread (for example, Brie) although some drier varieties of soft cheeses are more crumbly (for example, queso fresco).Whether Listeria grows in a cheese—and how well it grows—depends on many factors including whether the cheese is aged or fresh, how much fat or water is in the cheese, what the pH of the cheese is, and others.
A. Soft cheeses made from unpasteurized milk are the riskiest. Recently, Listeria outbreaks associated with cheese have also been associated with Mexican-style soft cheeses like queso fresco made from pasteurized milk that were likely contaminated during cheese-making.
|Type of Food||Higher Risk||Lower Risk|
Excerpted from "Common Foods: Select the Lower Risk Options," developed by the U.S. Department of Agriculture Food Safety and Inspection Service, and Food and Drug Administration. Go to page seven of "Food Safety for Transplant Recipients [PDF - 26 pages]" to see the entire table and learn more about food safety for vulnerable populations.
A. The federal agencies (CDC, FDA, and USDA) have several key resources on cheese that can be accessed below:
Cheese safety for vulnerable populations
- Common Questions and Answers From Pregnant Women About Listeriosis [PDF - 2 pages] (FDA) (en Español [PDF - 2 pages])
- Fotonovela: Maribel's Story - How eating Queso Fresco harmed her unborn baby (FDA) (en Español)
- Preventing Listeriosis In Pregnant Hispanic Women in the U.S. - Community Educator's Guide To A Serious Foodborne Risk (FDA) (en Español)
- Protect Your Baby and Yourself (en Español) (USDA)
Did you know that how you handle and prepare foods affects your risk for foodborne illness, sometimes called food poisoning?
Cheese safety – general
- Reducing the Risks of Foodborne Listeria (FDA)
- Let’s Talk About Listeria [MP3 - 6 minutes] (en Español [MP3 - 6 minutes]) (USDA
Cheese and industry
Cheese and raw milk
Q. Where can I find more information on common foods and ways to reduce my risk of Listeria and other foodborne infections?
A. The following resources can help you identify who is at greatest risk of Listeria and foodborne illnesses and steps that can be taken to protect yourself.