'', the bacterium responsible for
listeriosis Listeriosis is an infection caused by the bacterium
Listeria monocytogenes. The outbreak was determined to originate from Jensen Farms in
Holly, Colorado after
Listeria monocytogenes was found in cantaloupe samples at a Jensen Farms store in
Denver, Colorado and at the farm's packaging plant. The batch of cantaloupes had been shipped out over a period from July 29 through September 10 to twenty-five states, including Arkansas, Arizona, California, Colorado, Idaho, Illinois, Kansas, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Virginia, and Wyoming. The outbreak was first reported by the
Centers for Disease Control on September 12, where they stated that "fifteen people in four states had been infected". On September 21, a new report was released by the CDC, bringing the number of deaths to 13 and the number of confirmed cases to 72. The report also stated that further deaths were being investigated to determine if they had also been caused by
Listeria infection. The CDC report also stated that, as
Listeria "only sickens the elderly, pregnant women and others with compromised immune systems", the
median age of all the people that had been infected was 78. On September 30, an update was released by the CDC, reporting that as of 11 am (EDT) Sep 29, 2011 the number of confirmed cases was 84, number of deaths was 15 and the number of states involved was 19. On October 4, the CDC updated their report to 100 infected individuals in 20 states and a total of 18 deaths from the outbreak. The outbreak was shown to have continued to spread to new states, with the CDC update on October 7 stating that the number of cases had risen to 109 in 23 states and that three more people had died to bring the death toll to 21. The CDC update on October 12 put the number of cases at 116 with 23 deaths. An update on October 18 increased the number of cases to 123 and the number of deaths to 25. The October 25 update raised the number of cases to 133, with three more people dying to raise the total to 28. A final update on August 27 confirmed 147 cases and 33 deaths. Fatalities occurred in Colorado (9), Indiana (1), Kansas (3), Louisiana (2), Maryland (1), Missouri (3), Montana (1) Nebraska (1), New Mexico (5), New York (2), Oklahoma (1), Texas (2), and Wyoming (2). Among persons who died, ages ranged from <1 to 96 years, with a median age of 78 years. No list of retailers selling the infected cantaloupes was released by either the government or Jensen Farms. Although the last shipment was September 10 and the fruit had a two-week shelf life, as of September 29, the number of illnesses and deaths were expected to continue rising, because the incubation period could exceed one month. Recalls by retailers which had sold the Jensen Farms cantaloupes included
Kroger (September 15),
Safeway (September 15),
Aldi (September 16), and
US Foods (September 16).
FDA investigation An investigation by the
Food and Drug Administration (FDA) found that the contaminated cantaloupe harvest contained four separate
Listeria monocytogenes strains, which the governmental agency found to be "unusual", but was still trying to determine the reason. Water contaminated with
Listeria was also found on the floor of the packing plant and it was determined that the workers moving around the plant had spread it, as the contaminated water was also found on the cantaloupe
conveyor belt. It was noted by officials that Jensen Farms had "passed a food safety audit by an outside contractor" six days before the outbreak. How the
Listeria bacteria first came to be in the plant remains unknown, as the soil on the farm was determined to be clear of the bacteria. It is suspected, however, that a "dump truck used to take culled melons to a cattle farm...could have brought bacteria to the facility". Furthermore, bacteria growth may have been aided by condensation stemming from the lack of a pre-cooling step to remove field heat from the cantaloupe before cold storage.
House Energy and Commerce Committee investigation On October 21, the
House Energy and Commerce Committee, a committee panel of the
United States House of Representatives, began its own investigation into the outbreak. The Committee "requested a staff briefing from Jensen Farms" and all of the documents they had on the incident. They also requested information from the FDA, CDC, and other governmental groups. ==Jensen Farms response==