CDC Warning: Deadly Listeria in Cantaloupe

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1 Dead, 14 Hospitalized in 4 States; Nationwide Alert Over Colorado Cantaloupe

By Daniel J. DeNoon
WebMD Health News

Reviewed by Laura J. Martin, MD

Sept. 13, 2011 -- Cantaloupe from the Rocky Ford region of Colorado may carry deadly listeria bacteria, the CDC warns.

So far the outbreak has caused 15 hospitalizations -- including one death -- in four states: Colorado (11 cases), Nebraska (one case), Oklahoma (one case), and Texas (two cases).

The CDC has issued a nationwide warning for consumers to avoid fruit "marketed as cantaloupes harvested in the Rocky Ford region."

Listeria monocytogenes bacteria cause a disease called listeriosis. Listeriosis primarily affects older adults, pregnant women, newborns, and people with a weakened immune system. It also affects people with cancer, diabetes, alcoholism, liver disease, or kidney disease.

In the current outbreak from cantaloupe, all illnesses began after Aug. 15. Cases after Aug. 26 might not yet be reported.

The 15 people infected during this outbreak range in age from 38 to 96. Most are over age 60; 73% are female.

Lab tests have identified the outbreak strain of listeria in cantaloupe collected from grocery stores and from the home of a case patient. Investigations show the cantaloupes came from the Rocky Ford region of Colorado. The CDC is trying to determine a more specific source of contamination.

Many people who are exposed to the disease may not have symptoms. Severe symptoms indicate the bacteria have escaped the digestive tract and are spreading throughout the body. Listeriosis often results in fatal meningitis or encephalitis. Of the estimated 1,600 U.S. cases of listeriosis each year, there are 260 deaths.

Listeriosis Symptoms

Listeriosis usually begins with diarrhea or other intestinal symptoms. Patients soon develop fever and muscle aches. What happens next depends on a person's risk factors:

• While pregnant women usually get a mild flu-like illness, listeria infection can cause miscarriage, stillbirth, premature delivery, or fatal infection of the newborn.
• Other adults may develop headache, stiff neck, mental confusion, loss of balance, and convulsions.

Foods typically linked to listeriosis are deli meats, hot dogs, and soft cheeses made with unpasteurized milk. Produce is less often linked to outbreaks, although listeria occurs in soil and water. Listeria is killed by cooking, but it can grow and multiply in refrigerators.

How to Avoid Listeria

Since contaminated cantaloupes may still be in grocery stores or in people's homes, the CDC has issued this advice:

• People at high risk for listeriosis, including older adults, people with weakened immune systems, and pregnant women, should not eat cantaloupes marketed as coming from the Rocky Ford region of Colorado.
• Consumers who have cantaloupes in their homes can check the label or inquire at the store where they purchased it to determine if the fruit was marketed as coming from the Rocky Ford region of Colorado.
• Listeriosis primarily affects older adults, people with weakened immune systems, pregnant women, and newborns. People who think they might have become ill from eating possibly contaminated cantaloupes should consult their doctor immediately.
• Cantaloupes marketed as coming from the Rocky Ford region should be disposed of in a closed plastic bag placed in a sealed trash can. This will prevent people or animals from eating them.

As other foods besides cantaloupes can carry listeria, the CDC recommends these general steps to avoid listeriosis:

• Rinse raw produce, such as fruits and vegetables, thoroughly under running tap water before eating. Dry the produce with a clean cloth or paper towel before cutting them up.
• Thoroughly cook raw meat and poultry.
• Heat hot dogs, deli meats, and cold cuts until they are steaming hot just before serving.
• Do not drink raw (unpasteurized) milk and do not eat fresh soft cheeses that have unpasteurized milk in them, especially Mexican-style cheeses like queso fresco.
• Be sure that your refrigerator is at or below 40 degrees F and your freezer is at or below 0 degrees F by using a refrigerator thermometer.

SOURCES: News release, CDC.CDC web site. ©2011 WebMD, LLC. All Rights Reserved.