Listeria Causes and Treatment
Posted on 20 April 2015
If you eat food contaminated with the Listeria bacteria, you could get so sick that you have to be hospitalized. And for certain vulnerable people, the illness could be fatal.
A number of food brands have recalled their products over Listeria concerns: all of Blue Bell's ice cream products, Taylor Farms in North Carolina spinach, Sabra Hummus, Costco Canada chicken, and others.  
What is Listeria and how does it cause food poisoning?
Listeria (pronounced liss-STEER-ē-uh) is a bacterium that can grow under either anaerobic (without oxygen) or aerobic (with oxygen) conditions. Of the six species of Listeria, only L. monocytogenes (pronounced maw-NO-site-aw-JUH-neez) causes disease in humans.
These bacteria multiply best at 86-98.6 degrees F, but also multiply better than all other bacteria at refrigerator temperatures. 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 that you and your family will become sick.
Listeria has been linked to a variety of ready-to-eat foods including:
- 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
- Refrigerated smoked seafood
- Raw sprouts
Many cases of infection, however, don't have an identifiable source.
Listeria infections may cause symptoms such as fever, stiff neck, vomiting, diarrhea, lethargy, difficulty breathing, and poor feeding. Pregnant women who develop listeriosis may only have mild flu-like symptoms, but they are at risk for premature delivery, miscarriage, and stillbirth.
People who have weakened immune systems are at particular risk for developing the more serious illnesses from listeriosis, including pneumonia, meningitis, and sepsis.
Fortunately, cases of listeriosis are relatively uncommon. The earlier listeriosis is detected and treated, the better, since it can cause serious and life-threatening infection. And particularly if you are pregnant or in one of the other high-risk groups, avoiding certain food and drinks can reduce your risk of getting this infection.
Listeriosis is usually treated with antibiotics in the hospital through an intravenous catheter (IV) through a vein. Treatment lasts for about 10 days, but that can vary depending on the body's ability to fight off the infection.
Children whose immune systems are compromised by illness or infection, such as cancer or HIV, are more likely to develop severe listeriosis infections and may need further treatment. In healthy people with gastroenteritis due to Listeria, symptoms often last only 2 days and they recover completely.
There are no vaccines against the bacteria that cause listeriosis. But you can help protect your family with these food safety precautions:
- Always cook food (especially meat and eggs) thoroughly to the proper internal temperature.
- Wash fruits and vegetables well before eating.
- Only drink pasteurized milk, and make sure that milk is refrigerated at the appropriate temperature, which is below 40°F (4°C).
- Avoid foods made from unpasteurized milk.
- If you're in a high-risk group, avoid soft cheeses such as feta, Brie, Camembert, blue-veined cheeses, and Mexican-style cheeses (like queso fresco).
- Reheat precooked, prepackaged foods — such as deli meats or hot dogs — to steaming hot temperatures, especially if you're pregnant.
- Carefully wash hands and utensils after handling raw foods.
When to Call the Doctor
Call your doctor immediately if your child develops rapid or labored breathing, a fever, poor feeding, vomiting, dehydration, a high-pitched cry, lethargy (excessive sleepiness), or irritability. If your child has listeriosis, the doctor can rule out any other illnesses and start treatment.
Listeria monocytogenes (CDC) - General information on diagnosis, treatment, prevention, and more.
Listeria monocytogenes (USDA) - General information plus directives and notices, compliance guidelines, and more.
Listeria Infections (NIH MedlinePlus) - Trusted health information on causes, symptoms, treatment, and prevention.