Listeria in Cantaloupes: Deadliest Outbreak in a Decade

At Least 13 People Have Died From Cantaloupes Tainted With Listeria Bacteria

By Brenda Goodman
WebMD Health News

Reviewed By Laura J. Martin, MD

Sept. 28, 2011 -- The CDC says 72 people have been sickened and 13 have died as a result of eating cantaloupes tainted with listeria bacteria, making it the deadliest outbreak of food-borne illness in the U.S. in a decade.

State officials say they are investigating three more deaths -- one each in New Mexico, Kansas, and Wyoming -- that may also be connected to the contaminated Colorado cantaloupes.

The new numbers mean that the death toll has outpaced the number of deaths tied to an outbreak of salmonella in peanut products nearly three years ago. Nine people died in that outbreak.

According to the CDC, this is the third deadliest outbreak of food-borne illness since the agency began keeping records. In 1985, cheese contaminated with listeria killed 52 people. In 1998, listeria-contaminated hot dogs killed 21 people.

The melons involved in the current outbreak, "Rocky Ford" brand cantaloupes sold by Jensen Farms, were recalled on Sept. 14.

But health officials warn that that people may still have recalled melons in their refrigerators. They have also been used in some cut-fruit salads.

Unlike other many other kinds of food-borne pathogens, listeria bacteria can continue to grow despite the cold temperatures of a refrigerator.

"If they can't confirm that it's not Jensen Farms, then it's best to throw it out," said CDC Director Thomas R. Frieden, MD, in a news briefing on Wednesday.

Officials also say that because it can take weeks for people to get sick after coming into contact with listeria bacteria, they expect the number of deaths and illnesses linked to the melons to rise.

"The time between when you consume it and when you get sick is longer than it is for many other bacteria," Frieden said, "so people who consumed it some time ago may continue to develop illness in the coming days and weeks."

The majority of deaths in the current outbreak have occurred in people older than 60.

Listeriosis Symptoms

Listeriosis, the illness caused by listeria bacteria, typically strikes vulnerable people, like the elderly, pregnant women, and those with weakened immune systems.

Infection from listeria bacteria starts in the stomach and intestines where it may cause diarrhea and other gastrointestinal symptoms. If it spreads beyond the gut, listeriosis causes flu-like symptoms including fever and muscle aches, headache, stiff neck, loss of balance, and convulsions.

Officials say that while states reacted swiftly to contain the outbreak, the source of the contamination is still largely a mystery.

"This is the first time we have seen listeria contamination in whole cantaloupes, and we're working very hard to determine how this happened," says FDA Commissioner Margaret Hamburg, MD.

Though it's the first time listeria has contaminated cantaloupes, it's not the first time the melons have made people sick.

Officials say 10 other outbreaks of food-borne illnesses in the last decade have been tied to cantaloupes. In seven of those outbreaks, the melons were tainted with salmonella. In three, they carried norovirus.

"It's still a good thing to eat fresh fruits and vegetables, and we encourage people to do that," Frieden said. "It's a good thing to wash them before you eat them and to wash your hands after handling food."

Listeria Hot Spots

So far, illnesses have been reported in 18 states in the West and Midwest.

Colorado and New Mexico have been hit the hardest. To date, 15 people have fallen ill in Colorado and two have died in that state. In New Mexico, 10 have gotten sick and four have died.

Other states reporting illnesses linked to the outbreak, according to the CDC:

  • California (1 illness)
  • Florida (1)
  • Illinois (1)
  • Indiana (2)
  • Kansas (5)
  • Maryland (1)
  • Missouri (1)
  • Montana (1)
  • Nebraska (6)
  • North Dakota (1)
  • Oklahoma (8)
  • Texas (14)
  • Virginia (1)
  • West Virginia (1)
  • Wisconsin (2)
  • Wyoming (1)

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SOURCES: News release, CDC. CDC news briefing, Sept. 28, 2011. Thomas R. Frieden, MD, director, CDC. Margaret Hamburg, MD, commissioner, FDA. News release, Wyoming Department of Health. News release, New Mexico Department of Health. ©2011 WebMD, LLC. All Rights Reserved.

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