Federal health officials said Wednesday more illnesses and possibly more deaths may be linked to an outbreak of listeria in cantaloupe in coming weeks.
So far, the outbreak has caused at least 72 illnesses, including up to 16 deaths, in 18 states, making it the deadliest food outbreak in the United States in more than a decade.
The heads of the Centers for Disease Control and Prevention and the Food and Drug Administration said consumers who have cantaloupes produced by Jensen Farms in Colorado should throw them out. If they are not sure where the fruit is from, they shouldn't eat it.
Neither the government nor Jensen Farms has supplied a list of retailers who may have sold the fruit. Officials say consumers should ask retailers about the origins of their cantaloupe. If they still aren't sure, they should get rid of it.
"If it's not Jensen Farms, it's OK to eat," said Dr. Thomas Frieden, director of the CDC. "But if you can't confirm it's not Jensen Farms, then it's best to throw it out."
Jensen Farms of Holly, Colo., says it shipped cantaloupes to 25 states, though the FDA has said it may be more, and illnesses have been discovered in several states that were not on the shipping list. A spokeswoman for Jensen Farms said the company's product is often sold and resold, so they do not always know where it went.
The recalled cantaloupes may be labeled "Colorado Grown," "Distributed by Frontera Produce," "Jensenfarms.com" or "Sweet Rocky Fords." Not all of the recalled cantaloupes are labeled with a sticker, the FDA said. The company said it shipped out more than 300,000 cases of cantaloupes that contained five to 15 melons, meaning the recall involved 1.5 million to 4.5 million pieces of fruit.
The FDA said the cantaloupes were exported and that the countries involved were notified. But officials declined to say which countries received the melons.
Dr. Frieden and FDA Commissioner Margaret Hamburg said that illnesses are expected for weeks to come because the incubation period for listeria can be a month or even longer. That means that someone who ate contaminated cantaloupe last week may not get sick until next month. Jensen Farms last shipped cantaloupes on Sept. 10. The shelf life is about two weeks.
"We will see more cases likely through October," Ms. Hamburg said.
The FDA said state health officials found listeria in cantaloupes taken from Colorado grocery stores and from a victim's home that were grown at Jensen Farms. Matching strains of the disease were found on equipment and cantaloupe samples at Jensen Farms' packing facility in Granada, Colo.
Sherri McGarry, a senior adviser in the FDA's Office of Foods, said the agency is looking at the farm's water supply and possible animal intrusions 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 health officials said this is the first known outbreak of listeria in cantaloupe. Listeria is generally found in processed meats and unpasteurized milk and cheese, though there have been a growing number of outbreaks in produce. Ms. Hamburg called the outbreak a "surprise" and said the agencies are studying it closely to find out how it happened.
Cantaloupe is often the source of outbreaks, however. Dr. Frieden said CDC had identified 10 other cantaloupe outbreaks in the last decade, most of them from salmonella.