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Cantaloupe Listeria Outbreak: 84 Sick, 15 Dead

The outbreak of listeriosis that has spread from a cantaloupe farm in Colorado to 19 states has sickened at least 84 people and killed 15, the Centers for Disease Control and Prevention reported Friday.

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That’s 12 more illnesses and two more deaths linked to Jensen Farms melons, with Arkansas and Alabama reporting their first patients. The confirmed cases so far since July 31:

Alabama: 1 illness

Arkansas: 1 illness

California: 1 illness

Colorado: 17 illnesses, 3 deaths

Illinois: 1 illness

Indiana: 2 illnesses

Kansas: 5 illnesses, 1 death

Maryland: 1 illness

Missouri: 3 illnesses, 1 death

Montana: 1 illness

Nebraska: 6 illnesses

New Mexico: 13 illnesses, 5 deaths

North Dakota: 1 illnesses

Oklahoma: 11 illnesses, 1 death

Texas: 14 illnesses, 2 deaths

Virginia: 1 illnesses

West Virginia: 1 illness

Wisconsin: 2 illnesses

Wyoming: 2 illnesses

Health departments in these states and others are investigating additional listeriosis cases to determine if they are part of the outbreak, the CDC said. Idaho, Montana and Wyoming each may have an additional suspect case and Kansas awaits lab tests results on two more cases, including another death.

Although the implicated cantaloupes were recalled by Colorado’s Jensen Farms on Sept. 14, more outbreak cases are expected to be reported because of the time lag between diagnosis and lab confirmation of infection. And up to two months can elapse between eating contaminated food and developing listeriosis because of the bacteria’s long incubation.

Listeriosis typically affects older adults and this outbreak follows that pattern. Patients range in age from 35 to 96, with a median age of 78; 88 percent are over 60.  Among 79 with available information about treatment, 78 (99 percent) had symptoms so severe they required hospitalization. Two women were pregnant when they became infected; the CDC said it is following the outcome of each pregnancy.

Listeriosis can cause a healthy, pregnant woman to have mild “flu-like” symptoms but it can be lethal to her baby, resulting in miscarriage, premature labor, stillbirth or neonatal infection.

In the CDC’s Morbidity and Mortality Weekly Report (MMWR), the health authorities who have been helping investigate the outbreak discussed its unusual features:

– This is the first listeriosis outbreak associated with melon.

– Four widely differing pulsed-field gel electrophoresis (PFGE) pattern combinations and two Listeria serotypes are associated with the illnesses.

– The number of illnesses is already unusually high and expected to climb higher. Only two U.S. listeriosis outbreaks, one linked to frankfurters that sickened 108 and one with Mexican-style soft cheese that sickened 142, have been larger.

– More lives have been lost than in any U.S. foodborne outbreak since a listeriosis outbreak in 1998.

There was microbiological proof of the source in this outbreak.  All four outbreak strains of Listeria monocytogenes were found on whole and cut cantaloupes from patients’ homes, on cantaloupes at grocery stores and on melons and equipment at Jensen Farms in Colorado.

But it was shoe-leather epidemiology that led health investigators to the farm.

On Sept. 2, the MMWR report recounted, the Colorado Department of Health, which typically sees about two cases of listeriosis every August, reported seven cases since Aug. 28. By Sept. 6, all seven Colorado patients had been interviewed and reported eating cantaloupe in the month before they became ill.

Three of the seven said the cantaloupes they ate were marketed under the brand “Rocky Ford.”

As other cases were reported from around the country, data from the first 19 outbreak-associated patients were compared with 85 cases of sporadic listeriosis reported in August from 2004 through 2010. Cantaloupe consumption was a common factor in all 19 of the 2011 cases (100 percent) versus 54 or the 85 people (64 percent) in the control group.

Tracebacks from retailers who sold the cantaloupes then converged on a single suppler — Jensen Farms, the CDC said.

CDC director Dr. Thomas Frieden has pointed out that Colorado’s fast work leading to the warning about cantaloupe and the recall of the tainted melons likely saved lives and prevented more illness. Colorado’s state health department is supported by the CDC as part of the federal Foodborne Disease Active Surveillance Network. Called FoodNet, the system tracks lab-confirmed cases of foodborne infection, and plays a vita role in monitoring and protecting the country from foodborne disease, especially at a time when state and local health department budgets are being slashed.

The CDC warned that the contaminated cantaloupes could still be in consumers’ homes and also advised consumers who had Jensen Farms cantaloupe in their homes to take extra precautions, because the pathogen can persist and grow, even after the melon has been discarded. It advised washing refrigerator walls and shelves, cutting boards, and countertops, then sanitizing them with a solution of 1 tablespoon of chlorine bleach in 1 gallon of hot water.

There continues to be confusion about where the contaminated cantaloupes were sold, and the CDC said not all the recalled melons were labeled with Jensen Farms stickers.  Consumers have been advised to ask their retailer, or throw out any cantaloupe of uncertain origin.

On Friday, after further reviewing shipment records, Jensen Farms said its whole cantaloupes were distributed in three more states – Indiana, Louisiana and Wisconsin – than had been previously disclosed. The cantaloupes were also shipped to Arkansas, Arizona, California, Colorado, Idaho, Illinois, Kansas, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Virginia, and Wyoming.

CDC Outbreak Map:

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© Food Safety News
  • Susan

    None of the articles I’ve read are clear if the lysteria is just on the outside and gets on the flesh when you cut it; or if it’s in the flesh to begin with. I’m in Maine so I’m not too worried but my elderly mother is in CA.

  • mrothschild

    Susan: Yes, bacteria can lodge in the rough, netted rind of cantaloupe and get into the edible flesh via the knife when the melon is cut. But bacteria also can get into the fruit through nicks if the rind is damaged in the field, at harvest or during processing. The FDA and CDC say that if you know your cantaloupe was not from Jensen Farms, it should be OK. But if you have doubts, throw it out.

  • kmbrly

    An estimated 85% of cases of Listeria infection are from deli meats, not melons. While fruits and vegetables can become contaminated they are a significantly lower risk than meat and dairy. It’s important to keep things in perspective and understand which food sources put us at the highest risk for Listeria or other microbial infections. For more information check out Dr. Michael Greger’s article here: http://nutritionfacts.org/?p=4542

  • Anonymous Famer

    The recent deaths from contaminated cantaloupes are tragic. Lost in the media headlines is the death of a farm and bankruptcy of a family. Who in their right mind would become a farmer knowing you could lose everything as a result of a contamination event you can’t control and experts can’t identify. Maybe we should sell the farm. Find somebody else to grow your food.

  • mrothschild

    It remains to be seen whether this contamination was an event that couldn’t be controlled and that experts can’t identify. We haven’t been told yet what the experts have found. Roy Costa, who has been involved in more than 60 investigations of foodborne illness, once wrote that in most outbreaks there is evidence of major sanitation deficiencies, pest problems, serious time and temperature issues and/or personal hygiene issues.

  • Mary Rothschild

    Susan: Yes, bacteria can lodge in the rough, netted rind of cantaloupe and get into the edible flesh via the knife when the melon is cut. But bacteria also can get into the fruit through nicks if the rind is damaged in the field, at harvest or during processing. The FDA and CDC say that if you know your cantaloupe was not from Jensen Farms, it should be OK. But if you have doubts, throw it out.

  • Mary Rothschild

    It remains to be seen whether this contamination was an event that couldn’t be controlled and that experts can’t identify. We haven’t been told yet what the experts have found. Roy Costa, who has been involved in more than 60 investigations of foodborne illness, once wrote that in most outbreaks there is evidence of major sanitation deficiencies, pest problems, serious time and temperature issues and/or personal hygiene issues.

  • http://nutritionfacts.org Alexandra

    85% of cases of Listeria infection are from deli meats.
    While lower risk sources-such as fruits (cantaoupe) and vegetables-can become contaminated, we need to put things into perspective by understanding which foods put us at highest risk for Listeria or other microbial infections.
    The Director of Public Health and Animal Agriculture at the Humane Society of the United States, Dr. Michael Greger M.D. says:
    “This is evidently the first time cantaloupes have been considered a culprit. The FDA/USDA Listeria risk assessment identifies deli meats as the only “very high risk” food category, accounting for an estimated 85% of cases. On a per serving basis, deli meats were identified as the riskiest, followed by hot dogs, meat pâté, unpasteurized milk, and seafood. Other dairy products, including cheese and pasteurized milk, fell into the moderate risk category, while fruits and vegetables were classified as low risk, coming in at relative risk ranking of 14 and 18, respectively (the top 13 riskiest food groups were all meat and dairy).”
    Anyone concerned about Listeria, or other harmful outbreaks, MUST READ Dr. Greger’s full post!
    COPY AND PASTE THIS URL TO READ FULL POST:
    http://nutritionfacts.org/blog/2011/09/30/cantaloupe-and-listeria-an-estimated-85-of-cases-are-from-deli-meats-not-melons/