MICHELE NORRIS, Host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
MELISSA BLOCK, Host:
And I'm Melissa Block. It is the deadliest outbreak of food borne illness in the U.S. in more than a decade. Disease caused by listeria bacteria has been traced to cantaloupes grown on a farm in Colorado. Seventy-two people in 18 states have gotten sick, including two pregnant women. At least 13 people have died.
And as NPR's Nell Greenfieldboyce explains, more people are likely to fall ill before the outbreak is over.
NELL GREENFIELDBOYCE: Listeria infection is rare, but it can be deadly. It's especially dangerous for the elderly, pregnant women and their fetuses or people with weakened immune systems.
And here's the problem for scientists investigating an outbreak. After people get infected by food contaminated with the bacteria, it can take weeks for them to start having symptoms like fever and muscle aches.
THOMAS FRIEDEN: So figuring out exactly what they ate one, two, three weeks or longer ago and where they got that food from and what brand it is is quite a complicated investigation.
GREENFIELDBOYCE: Thomas Frieden is the director of the Centers for Disease Control and Prevention. He says, earlier this month, investigators were able to figure out that six people in this outbreak had eaten cantaloupe. Cantaloupe grown by a single producer in Colorado called Jensen Farms.
FRIEDEN: We're quite confident that the current outbreak is localized to Jensen Farms from all of the information we've seen so far.
GREENFIELDBOYCE: That cantaloupe has been recalled, both whole fruit and packages of cut up melon. But Frieden says not all of the Jensen Farms cantaloupe has a label saying so. Because cantaloupe may still be in people's fridges and also because it takes so much time for people to show symptoms after eating contaminated food.
FRIEDEN: Unfortunately, we do anticipate that case numbers will continue to rise over the coming weeks.
GREENFIELDBOYCE: Here's his advice.
FRIEDEN: If you know the cantaloupe in your fridge is not Jensen, then it's OK to eat. However, if in doubt, throw it out.
GREENFIELDBOYCE: He says, unlike other bacteria that cause food borne illness, listeria actually likes refrigeration. It flourishes at cold temperatures. Cantaloupe has never been linked to listeria infection before.
Chris Urbina is the head of Colorado's Department of Public Health and Environment. He says scientists have taken samples for testing from all around Jensen Farms, from places like fields and trucks.
CHRIS URBINA: To try to find out what actually happened and how the cantaloupe got contaminated.
GREENFIELDBOYCE: Listeria is widespread in the environment. It's found in dirt. Animals can carry it.
David Acheson used to be the food safety chief at the Food and Drug Administration. Now, he's with a consulting firm called Leavitt Partners. He says the contamination could have happened in the field, through irrigation or harvesting, but he thinks it's more likely to have happened as cantaloupes were gathered together and prepared for market.
DAVID ACHESON: If they were all going through some common wash just simply to wash off soil and dirt and the wash or the spray was contaminated with listeria, then what you're doing is essentially giving the cantaloupes a nice coating of listeria.
GREENFIELDBOYCE: He says whatever this cantaloupe investigation uncovers should point to ways to improve food safety in the future.
Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.