An outbreak of food-borne illnesses that have killed four people and sickened nearly three dozen others is linked to cantaloupe produced at a Colorado farm, the Food and Drug Administration confirmed Monday.
The FDA identified Jensen Farms, a family-owned operation that says it has grown cantaloupe for two decades, as the source of melons contaminated with a strain of Listeria, a dangerous but uncommon bacteria that thrives in cool temperatures.
The company had distributed about 300,000 cases of cantaloupe to 17 states before recalling its entire crop last week, just days after Colorado health officials flagged potential problems. On Friday, the state confirmed that Jensen Farms was the source of the tainted cantaloupe, and the FDA did the same Monday based on its own laboratory testing.
Although the company did not sell cantaloupe directly to retailers or wholesalers in Virginia, Maryland or the District, federal and company officials cannot guarantee that some of the melons did not make their way into the region. “We know who we sell to and who our customers are, but our customers may resell to another company,” said Amy Philpott, a company spokeswoman.
On Monday, some of the area’s largest grocery store chains — Giant Foods, Safeway and Whole Foods — said they did not carry any of the cantaloupe at issue.
The incident marks the first time that a Listeria contamination has been linked to whole cantaloupe and one of the few times it has been linked to produce in general, federal officials said. Listeria infections are more commonly associated with deli meats, hot dogs, unpasteurized milk and soft cheeses.
Unlike many other food-borne pathogens, Listeria multiplies in cold areas such as refrigerators, said Robert V. Tauxe, a deputy director at the Centers for Disease Control and Prevention. It can spread quickly in damp buildings, dripping off pipes or ceilings onto food.
While investigators have yet to determine how the cantaloupe became tainted, one of the simplest ways for people to get infected is by “passing a knife through the melon” and spreading the bacteria from the surface into the flesh, Tauxe said. The longer an infected melon sits in the refrigerator, the more quickly Listeria will grow.
On Monday, the CDC announced that 35 people in 10 states were infected, including four who died. A dozen of them were in Colorado. The remainder were in California, Illinois, Indiana, Montana, Nebraska, New Mexico, Oklahoma, Texas and West Virginia.
The FDA, which put out a separate statement on its investigation Monday, said that cantaloupe from other Colorado farms has not been linked to the outbreak.
David Acheson, managing director of food and import safety at consulting firm Leavitt Partners, said that Listeria infections are rare, but they result in hospitalization about 75 to 80 percent of the time. “It’s a very virulent bacteria in susceptible patients,” Acheson said.
The groups most vulnerable to serious illness from Listeria are the elderly and people with compromised immune systems. The CDC reported that people sickened by the cantaloupe ranged in age from 35 to 96, with a median age of 81.
Pregnant women must be especially careful because even though they may not develop symptoms if infected, the effects can be devastating to the fetus, resulting in miscarriages, stillbirths and birth defects.
Federal officials said that the number of affected consumers may rise because it can take several weeks for the bacteria to manifest itself into a clinical illness. Symptoms can include fever, muscle aches, a stiff neck and headaches.