In August 2012 the CDC began collaborating with public health officials in several states and the FDA to investigate a multistate outbreak of 16 Salmonella serotype Worthington infections reported by three states: California (12 patients), New Mexico (1 patient) and Washington (3 patients). These states were also seeing patients infected with Salmonella Braenderup linked to consumption of mangoes.

In interviews with patients infected with S. Worthington, 8 (89%) of 9 ill persons reported consuming mangoes in the the week before their illness began. These data suggested a possible connection between the outbreak of S. Braenderup and this outbreak. Furthermore one patient infected with S. Worthington was co-infected with the outbreak strain of S. Braenderup. Traceback efforts were not conducted to determine the source of these mangoes for persons diagnosed with S. Worthington. S. Worthington was not isolated during laboratory testing of mangoes.