• The CDC and FDA recently announced a recall of dairy products sold nationwide at Trader Joe’s, Costco, and Whole Foods that were linked to an outbreak of Listeria monocytogenes infections.
• For most people, a Listeria infection will only cause mild symptoms; for others that are high-risk, the same bacterial infection can be serious or deadly.
• Certain foods, including soft cheeses, deli meats, melons, and raw milk products, carry a higher risk of being contaminated with Listeria.

Earlier this month, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) announced a large recall of dairy products linked to an outbreak of Listeria monocytogenes infections.

The recall includes more than 60 items nationwide, all made with products manufactured by California-based Rizo López Foods. Cheeses (cotija, queso fresco, and ricotta, among others), yogurts, and sour creams have all been impacted by the recall, as have sandwiches, salad and taco kits, and dressings made with affected ingredients.

Recalled items were sold across the U.S. at various stores and under many different brand names, including Trader Joe’s, Costco, Whole Foods, and Walmart’s Marketside label.

The Listeria outbreak dates back to June 2014. Since then, a total of 26 people across 11 states have been sickened by the bacteria; 23 people have been hospitalized and two people have died.

An estimated 1,600 people get Listeria infections (listeriosis) each year, but most people don’t become seriously ill, and many may not know they have the illness. Certain high-risk people, however—those who are pregnant, newborns, the elderly, or people with weakened immune systems—can become severely sick and develop a more invasive illness. The CDC estimates that about 260 people die each year from Listeria infections.

The most recent Listeria outbreak isn’t the first, and it’s certainly not the last—here’s what to know about Listeria infections and how to stay safe.

How Do Foods Get Contaminated With Listeria?

Listeria monocytogenes, the bacteria that cause listeriosis, are a type of bacteria found everywhere, including soil, water, and in the digestive tracts of animals. Because they’re ubiquitous, the bacteria can contaminate fruits and vegetables through growing and harvesting or other foods during processing.

There are certain foods that have a higher risk of being contaminated with Listeria due to manufacturing processes or the way food is stored or eaten. Many ready-to-eat foods run a higher risk of being contaminated with Listeria since they’re not usually heated before eating.

Foods Most Likely to Be Contaminated With Listeria

• Unpasteurized soft cheeses (queso fresco, brie, blue-veined cheeses, etc.)
• Deli meats, cheeses, or salads
• Pâté or meat spreads
• Cold-smoked fish
• Sprouts
• Melons (cantaloupe, honeydew, watermelon)
• Raw milk or raw milk products

“These foods may be more likely to be contaminated because if it starts on a dairy farm—where hundreds of cows may be milked on the same machines, and then their milk is mixed together—that may lead to contamination,” said Dana Hunnes, PhD, MPH, RD, a senior clinical dietitian at the University of California, Los Angeles, and an assistant professor at the UCLA Fielding School of Public Health.

“As for downstream effects, these same cows who might be infected with Listeria have excrement, which, if not well managed, can runoff into streams and rivers,” Hunnes told Health. “[This] can contaminate fruit and vegetable farms, poultry farms, or other ranches that raise other animals.”

Listeria are also very hardy bacteria, which means they can survive for a long time, so it’s not unusual that the current outbreak has lasted for nearly a decade, according to Zhaoping Li, MD, PhD, Center Director and Division Chief, Clinical Nutrition at UCLA.

It’s important to note that the outbreak hasn’t been ignored since 2014—during that time, the CDC had investigated queso fresco and other types of cheese linked to listeriosis in 2017 and 2021, but the source of the illnesses had only recently been identified.

How Likely Are You to Get Sick From Listeria?

For most people, eating food contaminated with Listeria will lead to mild symptoms that usually start within 24 hours. “The most common symptoms of listeriosis are nausea, vomiting, and diarrhea,” said Hunnes. “For most healthy people who have a healthy immune system, symptoms should be self-limiting in severity and duration and shouldn’t last much more than a few days.”

But for some high-risk people—those who are pregnant, the very young or very old, or people with weakened immune systems—a Listeria infection can be dangerous and lead to a more invasive infection, which means the bacteria spread beyond the digestive system.

People who are pregnant may not feel severe symptoms, but a Listeria infection during pregnancy can lead to miscarriage, stillbirth, or other life-threatening problems with fetuses or newborns. For people who are high-risk but not pregnant, invasive listeriosis is fatal in almost 1 in 20 cases and can cause severe symptoms like fever, stiff neck, loss of balance, and seizures.

The CDC suggests people who have a higher risk of getting seriously ill from Listeria avoid foods that are more likely to be contaminated and instead choose safer options. People who are extra concerned about listeriosis may also want to avoid higher-risk foods.

For example, instead of choosing soft cheeses, hard cheeses like cheddar and parmesan are less likely to be contaminated. Melon you cut yourself, deli meats or hot dogs that are reheated to at least 165 degrees Fahrenheit, and pasteurized dairy products are also safe options.

Other preventive methods that can help protect you or others around you from listeriosis include washing your hands and avoiding cross-contamination, said Li. Thoroughly washing fruits and vegetables, cooking all meat to a proper internal temperature, and keeping your refrigerator at or below 40 degrees Fahrenheit can also add a layer of protection.