In 2012 the CDC collaborated with public health officials in many states and the U.S. Food and Drug Administration (FDA) to investigate a multi-state outbreak of Salmonella Typhimurium and Salmonella Newport infections linked to cantaloupe originating from Chamberlain Farms Produce, Inc. of Owensville, Indiana.
Public health investigators used DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis (PFGE) to identify cases of illness that may be part of this outbreak. They used data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.
A total of 261 individuals infected with the outbreak strain of Salmonella Typhimurium and Salmonella Newport were reported from 24 states: Alabama (25), Arkansas (6), Florida (1), Georgia (13), Illinois (36), Indiana (30), Iowa (9), Kentucky (66), Maryland (1), Michigan (8), Minnesota (2), Mississippi (7), Missouri (17), Montana (1), New Jersey (2), North Carolina (5), Ohio (5), Oklahoma (1), Pennsylvania (2), South Carolina (4), Tennessee (8), Texas (2), Virginia (1), and Wisconsin (9).
Among 257 persons for whom information was available, illness onset dates ranged from July 6, 2012 to September 16, 2012. Ill persons ranged in age from less than 1 year to 100 years, with a median age of 47 years. Fifty-five percent (55%) of ill persons were female. Among 163 persons with available information, 84 (51%) reported being hospitalized. Three deaths were reported in Kentucky. Results of antibiotic susceptibility testing indicated that this strain of Salmonella is susceptible to commonly prescribed antibiotics.
From August 14-16, 2012 investigators from the U.S. Food and Drug Administration (FDA) collected samples of cantaloupe at Chamberlain Farms. They also took samples in the farm’s cantaloupe packinghouse from surfaces that would likely harbor bacteria. This action was taken in cooperation with the Indiana State Department of Health. FDA samples of cantaloupe collected at Chamberlain Farms showed the presence of Salmonella Typhimurium with an indistinguishable DNA fingerprint as the outbreak strain. These samples also showed the presence of Salmonella Newport with a DNA fingerprint that was from the same outbreak strain that sickened 30 people in the states of Illinois, Indiana, Michigan, Missouri, Ohio, Virginia, and Wisconsin. The link was supported by trace back information collected by state officials in Indiana and Illinois which showed that patients consumed cantaloupe bought at stores supplied by Chamberlain Farms.
On October 3, 2012 the FDA released FDA Form (Inspectional Observations) for Chamberlain Farms. Federal inspectors observed poor sanitary practices at the firm’s cantaloupe packing shed. A third Salmonella serotype, Anatum, was isolated in samples obtained via environmental swabs collected from various locations and surfaces in the shed. FDA inspectors noted that food contact surfaces were not constructed or designed in a manner to allow appropriate cleaning. Multiple locations of the conveyor rollers and belts had accumulated black, green and brown buildup. There was standing water in the shed. The firm’s garbage receptacle was overflowing with garbage constituting an attractant, breeding place, or harborage for pests.