Listeria monocytogenes is a stealthy and resilient foodborne pathogen responsible for listeriosis, a potentially deadly infection. Unlike most bacteria, Listeria can thrive in refrigerated environments and withstand common food preservation methods, making it one of the most dangerous contaminants in the food supply. While listeriosis is relatively rare, it has one of the highest mortality rates of any foodborne illness, especially among pregnant women, older adults, and immunocompromised individuals.
Understanding which foods are most commonly linked to Listeria is essential for preventing illness. This article explores those high-risk foods, the reasons behind their susceptibility, and steps consumers can take to reduce their risk.
1. Ready-to-Eat Deli Meats and Hot Dogs
One of the most consistently implicated food groups in Listeria outbreaks is ready-to-eat (RTE) deli meats, including cold cuts, luncheon meats, and hot dogs. These foods often skip cooking at home and are consumed directly from the package.
According to the Centers for Disease Control and Prevention (CDC), RTE meats pose a high risk because Listeria can grow during refrigerated storage and may survive inadequate reheating or slicing equipment that hasn’t been properly sanitized. A 2020 study found deli meats to be the leading source of Listeria contamination in foodborne outbreaks over the past decade.
Prevention Tip: Always reheat deli meats and hot dogs until steaming hot, especially if pregnant or immunocompromised.
2. Soft Cheeses Made with Unpasteurized Milk
Soft cheeses such as brie, camembert, feta, queso fresco, and blue-veined cheeses are commonly associated with Listeria infections, especially when made from raw (unpasteurized) milk. The bacteria can contaminate milk during collection, handling, or storage and survive the cheese-making process if not pasteurized.
In 2021, an outbreak linked to queso fresco and other fresh cheeses infected at least 11 people and resulted in 1 death, according to the CDC.
Prevention Tip: Choose only cheeses labeled “made with pasteurized milk,” particularly if you fall within a high-risk category.
3. Smoked Fish and Refrigerated Seafood Products
Cold-smoked seafood, like lox, nova, smoked salmon, and trout—has also been linked to Listeria outbreaks. These products are typically not cooked after smoking, allowing any bacteria present to remain viable. Because Listeria can survive and grow in cold environments, refrigerated smoked seafood is particularly vulnerable.
A major outbreak in 2019 in Scandinavia linked to cold-smoked fish products led to several deaths and prompted widespread recalls in Europe.
Prevention Tip: Avoid refrigerated smoked seafood unless it is cooked in a dish, especially if you are pregnant or have a weakened immune system.
4. Refrigerated Pâtés, Spreads, and Dips
Refrigerated meat spreads, seafood dips, and pâtés made with liver or other organs have been implicated in Listeria outbreaks, especially those not subjected to heat treatment before packaging. Like deli meats, these items can harbor the bacteria and allow it to multiply during refrigerated storage.
In 2002, a multistate outbreak of listeriosis was linked to contaminated turkey pâté and led to multiple hospitalizations and deaths.
Prevention Tip: Use shelf-stable versions or heat refrigerated spreads to a safe temperature before consumption.
5. Unpasteurized Milk and Dairy Products
Unpasteurized milk and dairy products, including yogurt, cream, and butter made from raw milk, are frequent culprits in Listeria contamination. According to the U.S. Food and Drug Administration (FDA), raw milk is 150 times more likely to cause foodborne illness than pasteurized milk.
Contaminants can enter the milk supply at multiple points, from the cow to milking equipment to storage tanks, and if not pasteurized, those bacteria remain.
Prevention Tip: Always choose pasteurized milk and dairy products, especially for children and high-risk individuals.
6. Fresh-Cut Fruits and Vegetables
Although less common, Listeria has been detected in pre-cut or pre-packaged fruits and vegetables, including cantaloupes, lettuce, and sprouts. Contamination can occur during processing or packaging if equipment is not properly sanitized.
The 2011 cantaloupe outbreak from Jensen Farms in Colorado was one of the deadliest Listeria outbreaks in U.S. history, causing 147 illnesses and 33 deaths.
Prevention Tip: Wash fruits and vegetables under running water and consume pre-cut produce before the expiration date.
Final Note
Listeria monocytogenes is a formidable foodborne pathogen due to its ability to survive and grow in cold environments and ready-to-eat foods. While many of the products it contaminates are part of a typical diet, like deli meats, cheeses, and seafood, consumers can significantly reduce their risk by practicing good food safety habits, reading labels, and staying informed about recalls and outbreaks.
