Arizona health officials determined that a Salmonella-tainted salad served at the Arizona State Prison Complex located in Winslow caused 241 inmates and three employees to become ill in September 2015. Prison officials said inmates residing in the Kaibab unit began to feel ill on September 1 and the next day inmates in the Coronado unit became ill. Illness onsets continued for another five days. No one died in the outbreak.

On September 4 samples of various foods and environmental swabs were collected and sent to the Arizona Department of Health Services Bureau of State Laboratory Services for laboratory testing. One specimen described as “Sample Tray Meal 59 L” collected from the Kaibab unit was positive for Salmonella Enteritidis by PCR and culture. This finding led investigators to implicate lettuce or cabbage served to inmates at lunch in the Kaibab unit and at dinner in the Coronado unit on August 31.