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Info related to current Listeria outbreak linked to cantaloupes

The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are investigating a multistate outbreak of listeriosis, an illness caused by the bacterium Listeria monocytogenes. There have been cases of the illness reported in Wisconsin. The following information on the topic was provided by Barbara Ingham, UW-Madison food science professor and UW-Extension food safety specialist:

The FDA has issued a nationwide recall of cantaloupes from Jensen Farms in Colorado due to a link between those cantaloupe and listeriosis. This is the largest foodborne illness outbreak in the last 10 years. More than 72 illnesses have been linked to this outbreak and over 13 people have died. The Centers for Disease Control and Prevention in Atlanta is recommending that persons who want to avoid risk of listeriosis and the chance for cross contamination—especially high-risk groups, including older adults, persons with weakened immune systems, and pregnant woman—avoid eating Rocky Ford cantaloupes from Jensen Farms. Melons grown locally in Wisconsin are not part of this recall.

For more information: Cooperative Extension’s food safety page ( offers these links to information related to this topic (the focus of these resources is on prevention of illness caused by Salmonella, but the same general recommendations apply).

Following is information on Listeria monocytogenes and listeriosis that specifically addresses the current outbreak of illness.

Cases of listeriosis linked to this recall began on or after July 31, 2011. Those ill with listeriosis have ranged in age from 35 to 96 years, with a median age of 78 years old. Most ill persons are over 60 years old or have health conditions that weaken the immune system. Fifty-eight percent of ill persons are female.

About 800 cases of Listeria infection are diagnosed each year in the United States, along with 3 or 4 outbreaks of Listeria-associated foodborne illness. The foods that typically cause these outbreaks have been deli meats, hot dogs, and Mexican-style soft cheeses made with unpasteurized milk. Produce is not often identified as a source, but sprouts caused an outbreak in 2009, and celery caused an outbreak in 2010.

Listeriosis is a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes. The disease primarily affects older adults, persons with weakened immune systems, pregnant women, and newborns. Rarely, persons without these risk factors can also be affected.

A person with listeriosis usually has fever and muscle aches, often preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has invasive infection (meaning that the bacteria spread from their intestines to their blood stream or other body sites). The illness is especially troubling because of the high rate of hospitalization; in the current outbreak over 95% of those infected have had to be hospitalized. There is also a high mortality rate, with 13 deaths so far nationwide.

Listeriosis is treated with antibiotics. Persons in the high-risk category, including older adults, persons with weakened immune systems, and pregnant women, who experience flu-like symptoms within 2 months after eating contaminated food should seek medical care and tell the physician or health care provider about eating the contaminated food.