Listeria food poisoning: What it is and how to prevent it
If you eat food contaminated with bacteria called Listeria, you could get sick enough to end up in the hospital. For certain vulnerable people — an estimated 260 a year — the illness could even be fatal.
Unlike most bacteria, Listeria can grow and spread in the refrigerator. So if you unknowingly refrigerate Listeria-contaminated food, the germs not only multiply at the cool temperature, they could contaminate your refrigerator and spread to other foods there, increasing the likelihood for illness.
Listeria monocytogenes — Listeria — is a type of harmful bacteria that can be found in refrigerated, ready-to-eat foods (meat, poultry, seafood, and dairy — unpasteurized milk and milk products or foods made with unpasteurized milk), and produce harvested from soil contaminated with L. monocytogenes.
Many animals can carry this bacterium without appearing ill, and thus, it can be found in foods made from animals. You can also get listeriosis by eating contaminated foods processed or packaged in unsanitary conditions or by eating fruits and vegetables that are contaminated from the soil or from manure used as fertilizer. Listeria can hide unnoticed in food-processing equipment and contaminate food during production and processing, and some outbreaks have also been caused by foods that people may not think of as risky for Listeria, like celery, sprouts, and cantaloupe.
Those most at risk for listeriosis — the illness caused by Listeria monocytogenes — include pregnant women, older adults and people with compromised immune systems and certain chronic medical conditions (such as HIV/AIDS, cancer, diabetes, kidney disease, and transplant patients). In pregnant women, listeriosis can cause miscarriage, stillbirth, and serious illness or death in newborn babies.
Many germs can be spread through food — but some, like Listeria, can be deadly. Listeria is killed by cooking and pasteurization, but there is no type of immunization for Listeria available.
Most people found to have Listeria infection require hospital care, and about 1 in 5 people with the infection die. Listeria strikes hard at pregnant women and their newborns, older adults, and people with weakened immune system, and the illness can cause miscarriage and meningitis.
The symptoms can take a few days or even weeks to appear and may include fever, chills, muscle aches, diarrhea or upset stomach, headache, stiff neck, confusion, and loss of balance. In more serious cases, listeriosis could also lead to death.
Most of the time, pregnant women who are infected with listeriosis don’t feel sick, but can still pass the infection to their unborn babies without even knowing it. That’s why prevention of listeriosis is very important. In any case, if you experience any of the above symptoms, see your doctor or healthcare provider immediately.
Chart: Listeria details and prevention tips
Ready-to-eat deli meats and hot dogs
Refrigerated pâtés or meat spreads
Unpasteurized (raw) milk and dairy products
Soft cheese made with unpasteurized milk, such as Queso fresco, Feta, Brie, Camembert, Blue-veined, Panela – unless they’re made with pasteurized milk. (Make sure the label says, “made with pasteurized milk.”)
Refrigerated smoked seafood
Fever, stiff neck, confusion, weakness, vomiting, sometimes preceded by diarrhea
Duration of illness
Days to weeks
Who’s at risk?
People with weakened immune systems
Organ transplant patients who are receiving drugs to prevent the body from rejecting the organ
People with certain diseases/issues, such as:
HIV/AIDS or other autoimmune diseases
End-stage renal disease
What do you do?
If you are very ill with fever or stiff neck, consult your doctor immediately. Antibiotics given promptly can cure the infection and, in pregnant women, can prevent infection of the fetus.
How do you prevent it?
Do not drink raw (unpasteurized) milk, and do not eat foods that have unpasteurized milk in them.
Wash hands, knives and countertops after handling and preparing uncooked foods.
A cutting board should be washed with warm, soapy water after each use. Nonporous acrylic, plastic, or glass boards can be washed in a dishwasher.
Dish cloths, towels and cloth grocery bags should be washed often in the hot cycle of your washing machine.
It’s also important to wash hands with warm water and soap for at least 20 seconds before and after handling food.
Rinse raw produce, such as fruits and vegetables, thoroughly under running tap water before eating, cutting, or cooking. Even if the produce will be peeled, it should still be washed first.
Scrub firm produce, such as melons and cucumbers, with a clean produce brush, then dry the produce with a clean cloth or paper towel.
Keep uncooked meats, poultry, and seafood separate from vegetables, fruits, cooked foods, and ready-to-eat foods.
Thoroughly cook raw food from animal sources, such as meat, poultry, or seafood to a safe internal temperature.
Wash hands, knives, countertops, and cutting boards after handling and preparing uncooked foods.
Consume perishable and ready-to-eat foods as soon as possible.
Use precooked or ready-to-eat food as soon as you can. Do not store the product in the refrigerator beyond the use-by date.
Follow USDA refrigerator storage time guidelines:
Hot Dogs – store opened package no longer than 1 week and unopened package no longer than 2 weeks in the refrigerator.
Luncheon and Deli Meat – store factory-sealed, unopened package no longer than 2 weeks. Store opened packages and meat sliced at a local deli no longer than 3 to 5 days in the refrigerator.
Persons in higher risk groups should heat hot dogs, cold cuts, and deli meats before eating them.
Divide leftovers into shallow containers to promote rapid, even cooling. Cover with airtight lids or enclose in plastic wrap or aluminum foil. Use leftovers within 3 to 4 days.
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.
Clean up all spills in your refrigerator right away – especially juices from hot dog and lunch meat packages, raw meat, and raw poultry.
Clean the inside walls and shelves of your refrigerator with hot water and liquid soap, then rinse.
You can make your own sanitizer by combining 1 teaspoon of unscented bleach to one 1 quart of water, flooding the surface and letting it stand for 10 minutes. Then rinse with clean water. Let surfaces air dry or pat them dry with fresh paper towels. Bleach solutions get less effective with time, so discard unused portions daily.