Listeria: How to protect yourself from this common cause of food poisoning

Listeria infection is rare compared to other types of food-borne illness. But outbreaks from deli meats and other foods do occur from time to time.

What is Listeria?

Listeria infection is a food-borne illness caused by bacteria called Listeria monocytogenes. A Listeria infection is also called listeriosis. Most people develop listeriosis from eating contaminated foods.

Food poisoning from Listeria can be dangerous, or even deadly. About 1,600 people get a Listeria infection each year in the U.S., and about 260 people die from the disease.

How Listeria causes food poisoning

The bacteria that cause listeriosis can be found in moist environments, including soil, water, and decaying vegetation. Animals can also carry Listeria bacteria in their intestines without getting sick themselves. As a result, tood can become infected with Listeria during harvesting, processing, preparation, or storage.

If contaminated food is eaten, the bacteria can cause food poisoning.

Symptoms of listeriosis

The symptoms of listeriosis vary depending on whether the infection is limited to the gastrointestinal (GI) tract or has spread beyond the gut.

People infected with Listeria may feel symptoms within a few hours or days after eating contaminated food. Intestinal symptoms include diarrhea and vomiting. Symptoms usually resolve within three days, and most people feel better with rest and drinking plenty of fluids.

Invasive listeriosis, the term for listeriosis that spreads beyond the GI tract, can take several weeks to cause symptoms. Symptoms of invasive Listeria infection include:

• fever
• muscle aches
• fatigue
• headache
• stiff neck
• gastroenteritis
• confusion
• loss of balance
• seizures.

A severe Listeria infection may spread to the bloodstream or brain. Severe infections may cause life-threatening conditions such as sepsis, meningitis, or encephalitis.

Some pregnant women who develop listeriosis have no symptoms or have mild symptoms. However, infection during pregnancy can lead to miscarriage, stillbirth, premature birth, or a serious infection in the newborn.

Foods most likely to be contaminated with Listeria

The foods that are most likely to be contaminated with Listeria include:

• deli meats
• hot dogs
• unpasteurized raw milk
• unpasteurized soft cheeses
• raw sprouts
• smoked seafood.

While these foods have the highest risk of Listeria monocytogenes contamination, listeriosis can affect almost any improperly handled or prepared food.

How to reduce your risk of food poisoning

Some tips to reduce your risk of food poisoning from listeriosis or other food-borne illnesses, such as Salmonella poisoning, include the following:

• Set your refrigerator at 40^o  F (4^o C) or lower and your freezer at 0^o F (andndash;18 ^o C). Those temperatures can slow the growth of Listeria, which can grow even in cold temperatures. Use a refrigerator thermometer and adjust the settings if necessary.
• Use refrigerated foods by the date listed on the package. The longer you keep them, the higher the risk of Listeria growing.
• Clean your refrigerator regularly, and wipe up spills right away so Listeria doesn't have a place to grow.

Other steps you can take to reduce your risk of food poisoning include washing your hands before and after handling food, and using separate cutting boards and utensils for produce and raw meats or seafood.

A food thermometer can help ensure that meat, poultry, fish, and other foods are cooked to a safe internal temperature.

Raw pet food is another potential source of Listeria contamination, so take care when preparing your pet's meals.

Who is at greatest risk for severe illness from Listeria?

People at greatest risk for severe illness from Listeria include pregnant women, newborn babies, people ages 65 and older, and people with a weakened immune system, such as those being treated for cancer.

Listeria can harm a fetus even if the mother has mild symptoms. About one in four pregnant women who get listeriosis will miscarry or lose their baby shortly after birth.

What to know about food recalls

When a number of people get sick from eating or drinking the same contaminated food, it's defined as a food-borne disease outbreak. This can lead to a food recall by the U.S. government.

If a food in your home matches the details on a food recall notice, don't open or consume the product. Instead, bring the product to the place where you bought it for a refund, or dispose of it to make sure no one will consume it.

FoodSafety.gov, a U.S. government website, maintains a current list of food recalls and food-borne disease outbreaks, and advises what to do with a recalled product.

Treating food poisoning caused by Listeria

Most people with intestinal symptoms of listeriosis, such as vomiting and diarrhea, recover within a couple of days with rest and fluids.

Women who are pregnant will be prescribed an antibiotic to treat listeriosis. Antibiotics are also prescribed to people who are very ill or who are at risk of becoming very ill with an invasive Listeria infection.