In June 2010, a multistate outbreak of a matching strain of Salmonella Chester was detected in 44 cases from 18 states. Illness onset date ranged from April 4, 2010 to June 19, 2010. Among 43 patients with available information, 16 were hospitalized. There were no deaths. Investigators linked the outbreak to consumption of Marie Callender's Cheesy Chicken and Rice Frozen Entrees. The outbreak strain was isolated in 8 unopened frozen meals with production dates ranging from July 14, 2009 to March 12, 2010. ConAgra conducted a root cause analysis to identify common sources for ingredients used for the three productions dates where the outbreak strain was isolated. This extensive review identified a single poultry farm as a common supplier of chicken. The three production dates of interest suggested that cooked chicken might have been the contaminated ingredient.