• Posted: October 3rd, 2011 - 10:26pm by Doug Powell

    With 84 people confirmed sick from listeria in cantaloupe, including 15 deaths, some basic questions remain: where did the listeria come from, why was there so much that it affected so many people, and how did the listeria come into contact with the cantaloupe at Jensen Farms in Colorado?

    Elizabeth Weise of USA Today writes that cantaloupe growers, packers and sellers are not unanimous in deciding the best way to reduce the risk of listeria contamination on cantaloupes.

    "There are lots of places for bacteria to bind on the surface. It's like a mountain range under the microscope," says Doug Powell, a professor of food safety at Kansas State University, Manhattan. But there's not much consumers can do. If the listeria is on the rind, when you cut it open "it's going to cross-contaminate."

    About 85% of cantaloupe grown in the U.S.come from California and Arizona's arid high deserts, where they're watered using drip irrigation, which keeps them relatively clean. That means they don't need to be washed before being shipped, which experts say cuts down on the possibility of one contaminated melon tainting a whole vat of them as they're being washed.

    The other 15% are grown in the South, where rain is more likely to splatter them with mud and make them impossible to sell without washing. In the winter season, November through April, cantaloupe come from Mexico and Central America, where they're also more likely to get wet.

    Bringing cantaloupes into a packing shed, where they touch surfaces that have touched other melons and may be dunked in a tank of water to clean them, "has every opportunity to reduce risk, but equal or greater opportunity to contaminate," says Trevor Suslow, a food safety expert at the University of California, Davis, who has done extensive research on cantaloupes.

    Washing "is certainly a good practice, but you need to do that in an area that you won't introduce contamination" into other melons.

    Listeria is an especially problematic bacteria because it exists in the environment, in dirt and animals; once a colony starts growing on processing equipment, it can form biofilms that are difficult to remove. "They hide in the nooks and crannies," says Suslow. "You've got to go in with steam and stronger chemicals" to get rid of them.

    Craig Wilson, Costco's food safety director, says his company does require sellers to wash their cantaloupes, but what he's really moving toward "in the very near future" is a test-and-hold program. Growers and packers that want to sell him melons will need to test them for a broad range of potential pathogens such as "E. coli, salmonella, listeria," and not ship to him until the results come back negative, a process that takes between eight and 48 hours.

    "This not a bad industry, it's a good industry," Wilson says. "The cantaloupe folks are great, we just need to work together to get beyond this."

    A table of cantaloupe- (or rock melon) related outbreaks is available at

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  • Posted: October 1st, 2011 - 8:35pm by Doug Powell

    Pig’s ears are apparently used in meals around the world, such as Oreja de Cerdo in Spain (right); in North America, pig’s ears are most often used as dog treats.

    Thousands of packages of cooked pigs ears produced in Spain and distributed in southern France have been recalled after testing positive for Listeria monocytogenes.

    Our French friend Albert Amgar provided the link to the AFP story, and Amy translated on the way home from New Zealand this morning.

    The Roussillon Salaisons company which makes pork products and prepared meals in Perpignan initiated their own recall of the products in question from the concerned stores. In cases where the product had already been sold, it is requesting that people who still have the product not eat it and either destroy it or return it for a refund.

    Those who might have eaten the incriminated product and who have symptoms such as fever, with or without headache, are encouraged to consult their doctor and indicate what they have eaten.

    Pregnant women must be especially attentive to these symptoms, as should be immune-depressed and elderly people.

    The implicated products are 3200 vacuum-packed bags of plain cooked pigs ears and Galician style cooked pigs ears, both from the Régal Catalan brand. They were sold from July 4 in a few dozen Leader Price stores in Aquitaine, Midi-Pyrénées, Languedoc-Roussillon and Provence-Alpes-Côte-d’Azur, the company explained.

    They come from two imported lots from Spain with the numbers 07072011and a best by date of 5 October 2011, and 27062011, best by date 25 September 2011. Roussillon Salaisons insisted that the products were made by the Spanish firm Carnes Esman and not by Roussillon Salaisons itself. Roussillon Salaison emphasized that it does make certain pork products but in this case it only sold the pigs ears.

    Listeria was discovered during a routine test undertaken by a Leader Price store.
    Roussillon Salaisons was alerted to the problem Friday and said that they immediately asked all the stores to pull the product from their shelves and to put up a poster to notify consumers. But the health authorities asked that the company additionally alert consumers through the media, the company explained.

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  • Posted: October 1st, 2011 - 4:53am by Doug Powell


    As the number of confirmed cases of listeriosis reached 84 people in 19 states, including 15 deaths, natural-food types are blaming animal agriculture, others say a single food inspection agency would have prevented the outbreak, the government is telling people to wash their hands, and a group in Denver is using the tragedy to lobby for more paid sick days.

    It’s tired but true that major outbreaks of foodborne illness are reproessed through the political filters of punditry to advance a cause, rather than focus on the biological aspects of an outbreak – especially when the unknowns are numerous.

    Eric Jensen, the farmers at the center of the outbreak, has no idea how his cantaloupes became infected, and neither do the Food and Drug Administration investigators who have intermittently been in Holly, Colorado, a town of 800 people near the Kansas border.

    Regardless of how it happened, the situation has left the town and farm reeling and in fear. Jensen had to quit growing and shipping cantaloupes after the outbreak was discovered — a staggering blow to a region where cantaloupe has always been a proud local tradition.

    Sherri McGarry, a senior adviser in the FDA's Office of Foods, said the agency is looking at the farm's water supply and the possibility that animals wandered into Jensen Farms' fields, among other things, in trying to figure out how the cantaloupes became contaminated. Listeria bacteria grow in moist, muddy conditions and are often carried by animals.

    The water supply for farms in the Holly area comes from wells and irrigation ditches that tap the nearby Arkansas River. There's no shortage of thoughts around town about the potential causes.

    Proponents for Denver’s Initiative 300 that would let private employees and city workers earn up to 72 hours of paid sick days a year sent out a campaign flier that connects the ballot measure to the deadly listeria outbreak, upsetting opponents.

    The mailer by Campaign for a Healthy Denver features a photo of cantaloupe next to a dish of bow-tie pasta with the question: “What can you do to make your food safer? Make sure workers handling food are healthy.”

    The mailer continues: “There are many types of food contamination we can’t control. But we can help stop sick workers from handling our food by voting yes on Initiative 300.”

    Greg Sauber, co-owner of the Wash Park Grille, said, “It is outrageous and disgusting to use a tragedy for a political campaign. I don’t know where they are coming from with this.”

    The U.S. Centers for Disease Control published an outbreak investigative summary yesterday, including a description of how once cantaloupe was implicated, PulseNet, the national molecular subtyping network for foodborne bacterial disease surveillance, detected a multistate cluster with a fourth PFGE pattern combination; a sample of cantaloupe collected from the implicated farm yielded L. monocytogenes with this pattern, and interviews with patients revealed that most had consumed cantaloupe. Isolates with this pattern were then also considered to be among the outbreak strains.

    This outbreak has several unusual features. First, this is the first listeriosis outbreak associated with melon. Second, four widely differing PFGE pattern combinations and two serotypes (1/2a and 1/2b) have been associated with the outbreak. Third, this outbreak is unusually large; only two U.S. listeriosis outbreaks, one associated with frankfurters (108 cases) and one with Mexican-style cheese (142), have had more cases. Additional cases likely will be reported because of the long incubation period (usually 1--3 weeks, range: 3--70 days) and the time needed for diagnosis and confirmation. Fourth, this outbreak has the highest number of deaths of any U.S. foodborne outbreak since a listeriosis outbreak in 1998.

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  • Posted: September 29th, 2011 - 12:02am by Doug Powell

    As the official toll in the listeria-in-cantaloupe outbreak rose to 13 dead and 72 sick in 18 states, a major retailer said cantaloupe growers need to do more to prevent outbreaks of foodborne disease.

    “I don’t think the cantaloupe industry can continue on doing the very same thing and expecting a different result,” said Craig Wilson, the head of food safety for Costco, the Seattle-based warehouse retailer, which is regarded as a leader in requiring food safety measures from its suppliers. “It’s time for companies to get more aggressive. If they know this is going to happen, let’s step up and not let it happen.”

    William Neuman of the New York Times reports federal officials on Tuesday that there had been at least 19 previous outbreaks involving more than 1,000 illnesses and three deaths resulting from cantaloupe consumption since 1984. We count at least 36 outbreaks.

    Wilson further said Costco would consider setting standards for how melons are grown and how they are cleaned and handled after they are picked. He said the company would most likely require that suppliers test melons for pathogens before shipping them to Costco.

    He called on the industry to finance research into the best way to wash or clean cantaloupes to remove contaminants.

    Dr. Margaret Hamburg, commissioner of the Food and Drug Administration, said that investigators had yet to determine how the melons became contaminated.

    Trevor V. Suslow, an extension specialist at the University of California, Davis, who has done industry-financed research into food safety and cantaloupes, said that the fruit’s rough skin made it more susceptible to harboring unwanted bacteria.

    “You have these tremendous hiding places, if you will, nooks and crannies, lots of areas for microbes to get in and attach and hide,” Dr. Suslow said.
    It is best to keep cantaloupes dry to reduce the possibility that bacteria will grow on them, he said. In California, growers typically do not immerse melons in water to wash them and use chilled air to cool them.

    In other regions, he said, cantaloupes are often washed in a large tank or with a water spray and are cooled with sprays of cold water as well. Those techniques may be more likely to spread bacteria.

    Stephen F. Patricio, a melon shipper who is the chairman of the California Cantaloupe Advisory Board, a trade group, said that sales were plummeting, even though only melons from the farm in Colorado were implicated.

    “The entire melon category needs to look at the best practices and research that’s been done by the California industry and others to best analyze their own risks,” Mr. Patricio said. “Or we’re all going to continue to suffer.”

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  • Posted: September 24th, 2011 - 7:31am by Doug Powell

     I got up at 2 a.m. Friday for a 3 a.m. chat session after a video presentation about social media and food safety at the U.S. Centers for Disease Control's 15th annual PulseNet Update Meeting/seventh annual OutbreakNet Conference in Long Beach, Calif., only to be told the gene jockeys and epidemiologists had broken the Internet and couldn’t get a phone line.

    No worries, instead I chatted in hushed tones (trying not to wake the family) with JoNel Aleccia of msnbc about listeria and cantaloupe.

    Cantaloupe is particularly susceptible to contamination, ranking among the top five kinds of commonly tainted produce, along with spinach, lettuce, tomatoes and green onions, said Doug Powell, a professor of food safety at Kansas State University and publisher of a food safety blog.

    “What makes cantaloupe stand out is a couple of things. There’s the structure of the fruit. Think about a honeydew melon. They’ve smooth and very hard. Cantaloupe is very soft,” Powell told

    With its bumpy rind and succulent flesh, cantaloupe can easily become tainted at any point from field to table, Powell said. Bacteria on the skin are hard to remove, and they can be spread to the edible portion of the melon when a knife slices through. There’s some evidence that the porous skin might actually allow tainted water to permeate the flesh, he added.

    It’s not yet clear how the Jensen Farms cantaloupes were contaminated. FDA officials have found listeria in lab samples taken from equipment and fruit at the farm’s packing facility. But the bacteria can be present in soil or water, so the root cause has not yet been determined, said Doug Karas, a spokesman.

    Powell also said many outbreaks are confirmed only through interviews with ill people that reveal a common food source.. In the case of the new listeria outbreak, a health warning and recall was issued a week before experts actually detected the bacteria, possibly halting more infections and death.

    “Can you imagine the outcry if Colorado had waited an extra week to go public in the current outbreak?”

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  • Posted: September 23rd, 2011 - 5:52am by Doug Powell

    The hunt by Colorado scientists' to identify the source of a national listeria outbreak that has been linked to eight deaths involved two weeks of brainstorming, studying blood samples and confiscating half-eaten food from patients' refrigerators.

    Health officials also shopped for grocery-store cantaloupe before pinpointing a single farm in Holly as the source.

    State epidemiologist Alicia Cronquist thought it slightly odd when she learned two people were sickened by listeria bacteria within days.

    When two more reports arrived at the state health department in late August, Cronquist figured she was dealing with an outbreak.

    In the early stages of Colorado's investigation, county health authorities used 15-page questionnaires to interview patients and their families about what they ate and where they bought it.

    "The vast majority of people are elderly," Cronquist said. "The average age is in the 80s and they are quite ill. Their family members are at their bedside, and we are asking them to remember food that they ate a month ago. They are actually very difficult interviews."

    Meanwhile, the bacteria in patients' blood was isolated, and state microbiologist Hugh Maguire's labs deconstructed the DNA profiles to see whether they had listeria strains in common.

    Those profiles were uploaded into a CDC database of data from across the nation.

    Scientists pulled food from patients' homes, including typical listeria suspects like deli meats, hot dogs and dairy products.

    By Sept. 2, the state food lab determined that two patients had matching strains and two other patients matched in a separate strain. With hundreds of strains of listeria, two or more can be on the same food.

    Epidemiologists in patients' home counties interviewed the patients to look for patterns while the state health department faxed and emailed a listeria alert to doctors, hospitals and labs.

    When Cronquist checked a CDC database tracking foods that listeria victims reported eating, she found that all the patients she was tracking had eaten cantaloupe.

    Health authorities purchased 15 cantaloupes at three grocery stores and tested the rind and flesh for listeria bacteria. They also were testing patients' leftover melon. Maguire's lab fast-tracked the genetic matching, setting aside some of the lab's other, more routine work.

    A week after the first public warning, health authorities announced they had linked the source of the poisoning to cantaloupe.

    As more patient blood samples arrived at the state lab, they fell into three distinct strains. Cantaloupe taken from patients' refrigerators had the same strains but no sticker naming the farm. In interviews, though, patients volunteered that the cantaloupe said 'Rocky Ford' on it or was extra sweet.

    By tracking the melon purchases of patients back to the distribution trucks, investigators from the state and the Food and Drug Administration narrowed the focus to two farms and sampled soil and machinery.

    Two days after warning people not to eat Rocky Ford cantaloupe, health officials announced they had pinpointed the farm.

    Jensen Farms in Holly recalled its cantaloupes Sept. 14, while farmers in the Rocky Ford region miles away lamented how their produce was swept into early warnings about cantaloupe.

    Meanwhile, 7NEWS in Denver has confirmed the investigation is expanding beyond Jensen Farms and that a company that sprays treated human waste – biosolids -- confirmed to 7NEWS it has been contacted by investigators. State investigators confirmed they want to know if biosolids may have caused the contamination.

    Parker Ag Services vice president Mike Shearp told 7NEWS that government investigators have questioned him in recent days as to where those biosolids were applied. He said the substance was applied to a field directly across from a Jensen Farms field years ago.

    Shearp maintained that the contamination will not be traced back to his operation.

    Colorado State University animal science professor Lawrence Goodridge said, "If processed properly, there should not be pathogens. If they are not processed properly, if the wastewater treatment process breaks down, they could be (a) source of pathogenic bacteria such as salmonella, listeria and other pathogens."

    A spokeswoman with Jensen Farms said the company does not use biosolids in its operation.


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  • Posted: September 23rd, 2011 - 5:05am by Doug Powell

    The Kansas Department of Health and Environment (KDHE) has received word that the five isolates sent to the U.S. Centers for Disease Control match the multistate listeria-in-cantaloupe outbreak.

    Rocky Ford cantaloupes from Jensen Farms were distributed in Kansas and several other states.

    Kansas has eight cases of listeriosis reported since Aug. 26, with 5 cases now matching the multistate outbreak. Two of these eight patients have died and the causes of death are being investigated.

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  • Posted: September 21st, 2011 - 6:53pm by Doug Powell

    As of 5 p.m EDT on Sept. 20, 2011, a total of 55 persons infected with the 4 outbreak-associated strains of Listeria monocytogenes have been reported from 14 states. All illnesses started on or after August 4, 2011. The number of infected persons identified in each state is as follows: California (1), Colorado (14), Illinois (1), Indiana (1), Maryland (1), Montana (1), Nebraska (4), New Mexico (10), Oklahoma (8), Texas (9), Virginia (1), West Virginia (1), Wisconsin (2), and Wyoming (1).

    Expect those numbers to go up. The U.S. Centers for Disease Control says listeriosis illnesses in several other states are currently being investigated by state and local health departments to determine if they are part of this outbreak.

    Among persons for whom information is available, illnesses began on or after August 4, 2011. Ages range 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-nine percent of ill persons are female. Among the 43 ill persons with available information on whether they were hospitalized, all were hospitalized. Eight deaths have been reported, 2 in Colorado, 1 in Maryland, 4 in New Mexico, and 1 in Oklahoma.

    Collaborative investigations by local, state, and federal public health and regulatory agencies indicate the source of the outbreak is whole cantaloupe grown at Jensen Farms’ production fields in Granada, Colorado.

    A table of cantaloupe- (or rock melon) related outbreaks is available at

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  • Posted: September 19th, 2011 - 7:41pm by Doug Powell


    The U.S. Food and Drug Administration announced today it found Listeria monocytogenes in samples of Jensen Farms’ Rocky Ford-brand cantaloupe taken from a Denver-area store and on samples taken from equipment and cantaloupe at the Jensen Farms’ packing facility. Tests confirmed that the Listeria monocytogenes found in the samples matches one of the three different strains of Listeria monocytogenes associated with the multi-state outbreak of listeriosis.

    The U.S. Centers for Disease Control updated the official outbreak count to 35 persons infected with the outbreak-associated strains of Listeria monocytogenes, including four deaths, from 10 states.

    Jensen Farms voluntarily recalled its Rocky Ford-brand cantaloupes a week ago in response to the multi-state outbreak of listeriosis. Cantaloupes from other farms in Colorado, including farms in the Rocky Ford growing area, have not been linked to this outbreak.

    Jensen Farms is helping federal and state authorities determine how the cantaloupes became contaminated.

    The FDA’s root-cause investigation and environmental assessment includes the on-site expertise of FDA and state of Colorado microbiologists, environmental health specialists, veterinarians and investigative officers. The experts conducting the assessment will analyze the evidence, determine the most likely cause of contamination and identify potential controls to help prevent contamination in the future. The FDA will use the findings to help inform agency policy regarding Listeria and produce food safety best practices.

    Jensen Farms shipped the recalled cantaloupes from July 29 through Sept. 10 to at least 17 states with possible further distribution.

    For additional information about the recalled products, including product labels:

    A table of cantaloupe- (or rock melon) related outbreaks is available at

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  • Posted: September 15th, 2011 - 9:17am by Doug Powell

    The U.S. Centers for Disease Control reported this morning that 22 persons infected with the outbreak-associated strains of Listeria monocytogenes have been reported from 7 states. The number of infected persons identified in each state is as follows: Colorado (12), Indiana (1), Nebraska (1), New Mexico (4), Oklahoma (1), Texas (2), and West Virginia (1). Two deaths have been reported, one in Colorado and one in New Mexico.

    Collaborative investigative efforts of state, local, and federal public health and regulatory agencies have linked this outbreak to eating whole cantaloupe from Jensen Farms, of Granada, Colorado.

    The U.S. Food and Drug Administration is warning consumers not to eat Rocky Ford Cantaloupe shipped by Jensen Farms and to throw away recalled product that may still be in their home.
    Jensen Farms is voluntarily recalling Rocky Ford Cantaloupe shipped from July 29 through September 10, 2011, and distributed to at least 17 states with possible further distribution.

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