Listeria outbreaks in produce are rare, deadly

About 800 cases of listeria are found in the United States each year, according to the federal Centers for Disease Control and Prevention, and there usually are three or four outbreaks.

Produce has rarely been the culprit, but federal investigators say they have seen more produce-related listeria illnesses in the last two years. It was found in sprouts in 2009, celery in 2010 and now cantaloupe. “There are a lot of very good questions about where listeria is in the environment and how it gets in the fruit, and we don’t have all the answers,” said Dr. Robert Tauxe of the CDC. Tauxe said a likely scenario is that listeria – which often lives in wet, muddy conditions – from the farm or packing facility got on the outside of the fruit and then contaminated the edible portions when it was cut. Unlike most pathogens, listeria will continue to grow when refrigerated. He said that while rare, listeria can be deadly. On average, it can be fatal for one in five who fall ill. Colorado officials said Friday that the contaminated melons were whole fruit from Jensen Farms in the Rocky Ford region of Colorado, and have been recalled. Twenty-two people so far have been sickened in seven states: Colorado, Indiana, Nebraska, New Mexico, Oklahoma, Texas and West Virginia. Two deaths have been confirmed by CDC, one each in Colorado and New Mexico, and two more in New Mexico are under investigation. Colorado’s chief medical officer, Chris Urbina, said listeria found in samples taken from Jensen Farms’ cantaloupe match the strain of the bacteria found in those who fell ill in that state. “I’m confident that it’s the only farm,” Urbina said. To avoid listeria, the government has long warned those at-risk populations to avoid the most common carriers of the pathogen – hot dogs, deli meats, unpasteurized milk and cheeses made with unpasteurized milk. Now that listeria is showing up in produce, should consumers be concerned? No, say CDC and Food and Drug Administration officials. “It’s only when a strange alliance of the stars occurs you get an extraordinary event like this,” says Jim Gorny, a produce safety expert at the FDA. “It’s a surprise that we’d have an outbreak of this extent so we really want to understand what happened.” –Medical Xpress