In the on-going investigation of the outbreak, the FDA announced that dirty, corroded equipment recently purchased second-hand for the cantaloupe packing house is the likely source of the Listeria bacteria. The equipment was previously used for packing raw potatoes, which could have introduced Listeria-contaminated soil onto the equipment. The outbreak strains were also found in pools of stagnant water on the floor of the facility. The CDC provided an update on the outbreak on November 2nd.  The number of confirmed cases currently stands at 139 persons, and 29 have died.  The outbreak has sickened people across 28 states: Alabama (1), Arkansas (1), California (2), Colorado (39), Idaho (2), Illinois (3) Indiana (3), Iowa (1), Kansas (10), Louisiana (2), Maryland (1), Missouri (6), Montana (1), Nebraska (6), Nevada (1), New Mexico (15), New York (2), North Dakota (2), Oklahoma (11), Oregon (1), Pennsylvania (1), South Dakota (1), Texas (18), Utah (1), Virginia (1), West Virginia (1), Wisconsin (2), and Wyoming (4). The deaths occurred in Colorado, Indiana, Kansas, Louisiana, Maryland, Missouri, Nebraska, New Mexico, New York, Oklahoma, Texas, and Wyoming.  One pregnant woman is known to have had a miscarriage as a result of her infection.

The first Listeria cases from this outbreak were reported August 15, 2011. As the number of reported cases grew, an epidemiologic investigation in early September revealed that the source was cantaloupe; the source was narrowed to Rocky Ford cantaloupes on September 12, and on September 14 the Food and Drug Administration (FDA) issued a press release warning consumers not to eat cantaloupes produced by Jensen Farms in Holly, Colorado. On September 17, Colorado health officials announced they had isolated four strains of Listeria monocytogenes from Jensen Farms cantaloupes; other producers’ cantaloupes did not show the presence of any Listeria.

Jensen Farms has voluntarily recalled its entire 2011 harvest of Rocky Ford Cantaloupe from the marketplace. The recall encompasses more than 300,000 cases of cantaloupes, and represents 40 percent of the Rocky Ford-region output. The recalled cantaloupes were shipped from July 29 through September 10, and were distributed to at least 25 states, with further distribution possible. The cantaloupe may have a sticker labeled “Colorado Grown, Distributed by Frontera Produce, USA, Pesticide Free, Jensenfarms.com, Sweet Rocky Fords”, but not all of the recalled cantaloupes are labeled with a sticker. Consumers should consult the retailer if they have questions about the origin of a cantaloupe.

Laboratory testing by FDA has identified L. monocytogenes matching an outbreak strain in samples from equipment and cantaloupe at the Jensen Farms’ packing facility in Granada, Colorado. The FDA is also working with CDC, the states and other regulatory partners to investigate how the contamination occurred. Listeria outbreaks are usually associated with deli meats, unpasteurized cheeses and smoked refrigerated seafood products. This is only the third outbreak of listeriosis traced to fresh produce, and the first time a Listeria monocytogenes outbreak has been linked to whole cantaloupe. Health officials advise pregnant women, people over the age of 60 and those with compromised immune systems not to consume any of the recalled cantaloupes.