The jensen farms cantaloupe outbreak was the deadliest foodborne outbreak in the past 25 years?

By Linda Golodner
October 26, 2011

Bacterial contamination recently turned a nutritious, beta-carotene-rich melon into an agent of foodborne illness for some unfortunate consumers. The Denver Post reports October 26 that the multi-state outbreak, traced to Rocky-Ford brand cantaloupes grown at Jensen Farms in Holly, Colorado, has caused 28 deaths and that the Colorado cantaloupe industry will be subjected to stronger oversight. Although all Jensen Farms cantaloupes have been recalled, the Centers for Disease Control and Prevention says further cases of infection may surface in the coming months as Listeria monocytogenes bacteria continues to incubate in human hosts. This foodborne outbreak is the deadliest one in the past 25 years.

An investigation conducted by the Food and Drug Administration (FDA) identified several likely sources of contamination at Jensen Farms, where agricultural practices were not up to par. The report cites several potential factors contributing to the outbreak. These factors fall under two categories:

Cross-contamination of Listeria on farm surfaces

Cattle are known carriers of Listeria. The packing shed floor, cantaloupe-transport truck tires and farm equipment might have been contaminated with cattle waste, leading to cantaloupe contamination. Another possibility is that Listeria infected cantaloupes through contact with a used potato-washing machine.

Conditions favorable to Listeria growth

The FDA noted a refrigerator drain line allowed water to pool on the floor next to cantaloupe packing equipment, setting up a moist environment conducive to bacterial grow. Additionally, in a departure from normal procedure, cantaloupes were not pre-cooled prior to cold storage, which might have resulted in condensation on the melon surfaces, providing moisture to sustain bacteria. Unlike many other germs, Listeria can grow even in the cold temperatures of the refrigerator. And the uneven surface of cantaloupe provides many “hiding places” for dirt and germs.

According to FDA, the cantaloupe outbreak highlights the importance of employing good agricultural and management practices in packing facilities as well as in growing fields. FDA recommendations include assessing produce facilities and equipment design to ensure adequately cleanable surfaces, eliminating opportunities for the introduction, growth and spread of Listeria. Cleaning and sanitizing procedures were clearly inadequate at Jensen Farms.

Foodborne Illness Prevention for Consumers:

- Wash fresh produce thoroughly under running water just before eating, cutting or cooking. Even if you plan to peel the produce before eating or scoop it out as you would a melon, it is important to wash it first, according to www.foodsafety.gov. Use a clean produce brush to scrub the uneven surfaces of fruits like cantaloupe especially well because dirt and germs may be difficult to dislodge. Cut out any bruised areas.

FDA Directions for a Homemade Sanitizer for Food-contact Surfaces

Combine one teaspoon of unscented bleach to one quart of water, flooding the surface and letting it stand for 10 minutes. Then rinse with clean water. Let surfaces air dry or pat them with fresh paper towels.

Bleach solutions become less effective with time, so discard unused portions daily.

Clean and sanitize food-contact surfaces. The FDA web page, “Keep Listeria out of Your Kitchen” recommends cleaning hands and kitchen surfaces often in order to prevent Listeria spreading from one surface to another. FDA advises using warm soapy water on food preparation surfaces followed by sanitizing as an added precaution (see directions at right). FDA further recommends cleaning refrigerator walls and shelves regularly with warm water and liquid soap, followed by rinsing. Sanitize the refrigerator monthly, according to FDA, for added caution by using the diluted bleach solution and procedure described in the box at the right.
Be armed with knowledge. The website www.foodsafety.gov is an excellent source of information on food contamination issues. For example, the site explains that Listeria infection is 20 times more likely in pregnant women than in other healthy adults and can lead to miscarriage, stillbirth or life-long health problems. Knowledge is power, so learn all you can about preventing foodborne illness!

Linda Golodner is President Emeritus of the National Consumers League and Vice Chair of the Water Quality & Health Council.

By JoNel Aleccia

Potentially contaminated processing equipment and problems with packing and storage of whole cantaloupes at a Colorado farm likely led to the deadliest listeria outbreak in the United States in 25 years, which has so far claimed 25 lives in a dozen states, federal health regulators said Wednesday.

Pools of water on the floor of the Jensen Farms packing facility in Granada, Colo., equipment that was not easily cleaned and sanitized and failure to cool newly harvested cantaloupes before sending them to cold storage all contributed to the outbreak, the first-ever listeria contamination blamed on whole melons, federal Food and Drug Administration officials said Wednesday.

"We are quite confident and certain," that those factors led to the outbreak blamed so far for 123 illnesses in 26 states, said Sherri McGarry, senior advisor to the FDA's CORE Network in the Office of Foods, who spoke at a Wednesday press conference.

The news that the problem may have been prevented through basic sanitation practices stunned Jeni Exley, whose 84-year-old father, Herb Stevens of Littleton, Colo., has been hospitalized for nearly two months after a listeria infection caused by contaminated Jensen Farms cantaloupe. He might be able to return home finally this week, said Exley, 55, whose family is suing the farm with the help of Seattle food safety lawyer Bill Marler.

"Shame on them," said Exley. "What kind of statement can I give you without being too angry? It shouldn't have happened. They had control over it."

Investigators tested fruit samples and equipment from Jensen Farms and confirmed the presence of four outbreak strains of the listeria monocytogenes bacteria confirmed in the illnesses and deaths.

The FDA said Jensen Farms, which is based in Holly, Colo., had recently bought used equipment that was corroded and hard to clean.

For example, the equipment used to wash and dry cantaloupe showed signs of dirt and product build-up, even after it had been disassembled, cleaned and sanitzed, the FDA's report said. The equipment had been previously used to process raw potatoes, officials said, which could have left listeria bacteria behind.

In addition, a truck used to haul culled cantaloupe to a cattle operation was parked near the facility and could have introduced contamination to the facility, investigators said. Low levels of listeria in the field also could have introduced the bacteria into the packing facility. And the design of the plant allowed stagnant water to pool on the floor. The FDA had not inspected the farm before the Sept. 10 session that first detected listeria problems.

The FDA issued the company a warning letter detailing violations, but the investigation is still open.

Jensen Farms voluntarily has agreed to correct all problems found in the inspection, FDA Commissioner Dr. Margaret Hamburg told reporters. In addition, the firm has agreed not to process, pack or distribute produce until the agency approves.

The tragic deaths and illnesses have underscored the need for prevention at all levels of the food supply system, Hamburg said.

“If we’re to have a food safety system that truly prevents foodborne illness, we must all practice prevention,” she said.

The conditions at Jensen Farms were not indicative of the produce industry in general, FDA officials noted.

The outbreak has claimed lives in a dozen states, the Centers for Disease Control and Prevention said. They include six in Colorado, five in New Mexico, two each in Kansas, Louisiana, New York and Texas and one each in Indiana, Maryland, Missouri, Nebraska, Oklahoma and Wyoming. People who've died have ranged in age from 48 to 96 years, with a median age of 87.

Illnesses have occurred in 26 states in people aged younger than 1 to 96, with most cases occurring in people older than 60. Four illnesses were related to pregnancy, including a newborn who fell ill. One miscarriage has been reported.

The peak in illnesses appears to have occurred in mid-August and the number of illnesses reported now appears to be decreasing, said Dr. Barbara Mahon, deputy chief of the Enteric Disease Branch of the Centers for Disease Control and Prevention. But, the long incubation period for listeria means people could become ill up to two months after eating tainted fruit.

“It’s too soon to declare the outbreak over," Mahon said.

Federal investigators Wednesday painted a picture of rogue conditions at Jensen Farms that led to the deadly listeria outbreak, saying the company’s unsanitary cantaloupe handling flouted industry norms with dirty equipment, pooled water and lack of a cooling system.

The Food and Drug Administration said its “root cause” probe at the southeastern Colorado packer showed multiple places where normal background levels of listeria likely bloomed into deadly concentrations, from a dump truck to a produce washer designed for potato farms.

Federal officials said Jensen cannot resume production without their approval and may face further sanctions. They also warned cantaloupe operations in other states to take heed of their handling recommendations after the deadliest foodborne illness outbreak in more than 25 years.

Twenty-five people have now died from the Jensen Farms cantaloupe listeria, including six in Colorado. A pregnant woman also miscarried after contracting the listeria.

“We’ve been working around the clock to identify the lessons from this outbreak,” FDA commissioner Dr. Margaret Hamburg said.

“There’s no reason to believe these factors are indicative of practices throughout the industry,” FDA senior adviser Sherri McGarry said.

Federal agencies also acknowledged, though, their limitations in preventing future outbreaks.

They said a third-party auditor had been at Jensen Farms in August assessing many of the same factors cited in the FDA investigation. Yet the farm was still shipping, and grocery chains were still buying.

Even under a new Food Safety Modernization Act signed in January, packing facilities like the one Jensen used must only be inspected by the FDA every five to seven years. FDA officials said they will try to create accreditation standards for third-party auditors — often hired by the farms themselves or by grocers — to fill in gaps in federal or state inspections.

Jensen never came under a federal inspection before the August outbreak of listeria. The farm recalled all of its melons Sept. 14. Listeria cases and deaths may continue for another two weeks given the bacteria’s long incubation period.

Federal agents said they took numerous swab samples at Jensen on Sept. 10 and returned with a large team of environmental investigators Sept. 22. They did not find listeria bacteria in Jensen field soil or on cantaloupes still in the field.

That led them to believe the problems were in and around the packing shed, where common listeria bacteria can multiply in wet and cool conditions if the farm lacks sanitary measures.

Investigators found a dump truck used for discarded melons parked near the shed. It carried melons to a nearby cattle lot and could have tracked listeria back to the packing area.

They also found pools of water in walkways and at drains, providing more breeding ground for bacteria. A key piece of washing and sorting equipment came in from a potato operation this year, and it couldn’t be cleaned or sanitized properly for melons, the FDA report said.

Finally, the farm didn’t use either of the two melon cooling methods recommended by existing FDA guidelines. Most farms take melons still hot from the field and spray them with cold water, or pack them in crates with holes open to forced-air cooling.

Jensen packed warm melons directly in boxes that were then refrigerated, and that could produce condensation that promotes listeria growth.

The FDA’s warning letter to Jensen, released Wednesday, said 39 swabs were taken and tested from the Sept. 10 visit to the packing area, and 13 came back positive for listeria.

The high number “demonstrates widespread contamination throughout your facility and indicates poor sanitary practices in the facility,” the warning letter said.

“Jensen’s practices seem to be much different than the FDA has suggested” in industry guidelines, said Larry Good ridge, a microbiology expert with Colorado State University who has worked with many farms. The good news for other Colorado growers, Good ridge said, is they can reclaim the Rocky Ford image of safety and taste.

“All of the things they weren’t doing well are things they should have been doing all along,” said Bill Marler, a Seattle attorney specializing in foodborne illnesses who has filed many wrongful-death and injury lawsuits from the cantaloupe outbreak.

A Pueblo attorney working with Jensen Farms did not return calls for comment Wednesday.

Colorado Agriculture Commissioner John Salazar joined the federal conference call about the investigation and said Jensen is working “wholeheartedly” to correct the problems noted by the FDA.

The Jensen attorney has responded to the warning letter by saying the farm is working to correct all the problems and will cooperate with the FDA, the agency said.

State agriculture officials and local farmers will now struggle to resurrect the $8 million cantaloupe crop in Colorado. Even California growers have reported major drops in demand after the listeria scare.

Eric Hanagan, a cantaloupe grower in what farmers call the real Rocky Ford area, 90 miles west of Jensen’s operation, said he welcomed the report.

“I hope it just brings some closure to the issue and we as an industry can move forward,” said Hanagan, who will plant cantaloupes next year but not as many acres. The FDA guidelines “can make us better in the long run,” he said, though he said his farm already uses safe techniques.

Michael Booth: 303-954-1686 or

Key factors in the listeria outbreak

• A truck may have tracked listeria from a cattle feeding facility back to Jensen Farms.

• Washing and sorting equipment that used to be at a potato operation may have held listeria.

• Pooled water was a place for listeria to multiply.

• Floors and equipment were poorly designed for cleaning and sanitizing.

• No pre-cooling was done before cold storage.

FDA details possible sources of listeria

The FDA on Wednesday released its findings about potential sources of listeria on cantaloupe shipped from Jensen Farms and how it spread within the farm:

Source

• Listeria is a common bacteria in farm soil and animal feces, at low levels. A dump truck that carried discarded cantaloupe to a cattle feeder may have tracked cattle-related listeria back to Jensen. Investigators found it was often parked close to the Jensen packing shed.

• Potato washing and sorting equipment installed this year may also have brought a strain of listeria. Since potatoes are cooked, background levels of listeria are not a problem.

Spread

• The packing facility’s design allowed water to pool on the floor near equipment, drains and employee walkways. Background listeria can multiply in wet, cool environments.

• The packing shed’s floors and equipment were not designed to be easily cleaned or sanitized. Agents specifically mentioned the potato equipment design as resisting a thorough cleansing.

Growth

• There was no pre-cooling step to remove field heat from the cantaloupes before cold storage. As the cantaloupes cooled, there may have been condensation that promoted the growth of listeria.

FDA suggestions

• Use packing equipment designed to facilitate cleaning and sanitation of melon contact surfaces and constructed of materials that may be easily cleaned and sanitized.

• Validate and verify that melon wetting and brushing operations are not a potential source of melon contamination or cross-contamination.

• Cool and cold-store melons as soon as possible after harvest because delays in cooling when melons with netted rinds (such as cantaloupe) are wet from washing operations may allow for multiplication of human pathogens on the rind surface.