Listeria is one of the few foodborne bacteria that can grow in your refrigerator, which makes preventing it different from preventing most other types of food poisoning. The bacterium thrives between -1.5°C and 45°C, meaning standard fridge temperatures slow it down but don’t stop it. Prevention comes down to choosing the right foods, storing them properly, cooking to safe temperatures, and keeping your kitchen clean.
Why Listeria Is Harder to Avoid Than Most Bacteria
Most harmful bacteria stop multiplying once food is refrigerated. Listeria doesn’t. It can grow, slowly, at temperatures as low as 0°C (32°F). It also tolerates salt concentrations up to 13-14%, which means cured and brined foods aren’t automatically safe. These traits explain why Listeria outbreaks are so often linked to refrigerated, ready-to-eat foods that people assume are fine to eat straight from the package.
Symptoms of a mild intestinal infection (diarrhea, vomiting) typically show up within 24 hours and resolve in one to three days. But invasive listeriosis, the more dangerous form, can take up to two weeks to appear. At that point, symptoms include fever, muscle aches, stiff neck, confusion, and in severe cases, seizures. Pregnant women, older adults, newborns, and people with weakened immune systems face the highest risk of serious illness.
Foods Most Likely to Carry Listeria
The highest-risk foods share a common trait: they’re eaten without further cooking. Deli meats, cold cuts, and hot dogs are frequent culprits. Fermented and dry sausages like salami, chorizo, pepperoni, and summer sausage also carry risk. Prepared deli salads, including coleslaw, potato salad, tuna salad, and chicken salad, are another common source because they sit at refrigerated temperatures for extended periods.
Soft cheeses made from unpasteurized (raw) milk are particularly risky. That includes feta, brie, Camembert, and queso blanco. Soft cheeses made with pasteurized milk are safe. Refrigerated pâté, meat spreads, and smoked seafood round out the list. Fresh produce can also carry Listeria, especially pre-cut fruits and melons where the bacteria transfer from the rind to the flesh during slicing.
Set Your Refrigerator to 40°F or Below
Your refrigerator should be at 40°F (4°C) or below. Use a thermometer to verify this rather than relying on the dial setting, since built-in thermostats can be inaccurate. While this temperature won’t kill Listeria, it significantly slows its growth and buys you time on perishable items.
Opened deli meats and sliced luncheon meats should be eaten within three to five days. Don’t rely on smell or appearance to judge safety. Listeria doesn’t change the taste, texture, or odor of food the way some other bacteria do. If you won’t finish deli meats within that window, freeze them (they keep one to two months frozen).
Cook to the Right Internal Temperature
Heat reliably kills Listeria. Use a food thermometer and follow these minimums:
- Poultry (whole birds, breasts, thighs, ground): 165°F (73.9°C)
- Ground beef, pork, veal, and lamb: 160°F (71.1°C)
- Steaks, chops, and roasts (beef, pork, veal, lamb): 145°F (62.8°C), then rest for at least 3 minutes
- Fish and shellfish: 145°F (62.8°C)
- Eggs: 160°F (71.1°C)
- Leftovers and casseroles: 165°F (73.9°C)
Hot dogs and deli meats should be reheated until steaming hot (165°F) before eating, not served cold from the package. This single step eliminates the most common route of Listeria exposure for many people.
How to Handle Produce Safely
Rinse all fruits and vegetables under running water before eating, peeling, or cutting them. This step matters even for produce you plan to peel, like melons and avocados, because a knife blade drags bacteria from the outer surface into the flesh as it cuts through. Use a clean vegetable brush to scrub firm-skinned produce like cantaloupe and cucumbers.
Don’t use soap, bleach, or commercial produce washes. Plain running water is effective and won’t leave residues. Dry produce with a clean cloth or paper towel after rinsing to remove any remaining bacteria on the surface.
Prevent Cross-Contamination in Your Kitchen
Listeria spreads easily from raw foods to surfaces to ready-to-eat items. Wash your hands for at least 20 seconds before and after handling raw food. Use separate cutting boards for raw meat and produce, and wash boards, knives, and countertops with hot soapy water after each use. One important note: don’t rinse raw meat or poultry before cooking, as this splashes bacteria onto surrounding surfaces without making the meat safer.
Wipe up refrigerator spills immediately, especially drips from thawing meat. Listeria can colonize wet surfaces inside your fridge and then spread to other foods. Clean the inside walls and shelves periodically with hot water and mild dish soap, rinse, and dry with a clean cloth.
For disinfecting countertops and cutting boards, a bleach solution works well: mix 5 tablespoons (one-third cup) of bleach per gallon of room-temperature water, or 4 teaspoons per quart. Apply it to the surface and leave it visibly wet for at least one minute before wiping.
Extra Precautions During Pregnancy
Pregnant women are about 10 times more likely to get listeriosis than the general population, and the infection can cause miscarriage, stillbirth, or serious illness in newborns. The American College of Obstetricians and Gynecologists recommends pregnant women avoid unpasteurized milk and any foods made from it, refrigerated pâté and meat spreads, refrigerated smoked seafood, and all raw or undercooked meat, poultry, seafood, and eggs. Cooked sushi is safe; raw-fish sushi is not.
Hot dogs and luncheon meats are fine only if reheated to steaming hot immediately before eating. If you’re at a deli counter or restaurant and can’t verify the food has been reheated, skip it. These restrictions also apply to people with weakened immune systems and adults over 65, who face similarly elevated risks from Listeria exposure.