Initially unrecognized distribution of a commercially cooked meat product contaminated over several months with Salmonella serotype Infantis

An outbreak of salmonellosis occurred among 63 wedding participants. The ou tbreak was investigated through cohort, laboratory, and environmental studi es. Consumption of rice-dressing made from a commercially cooked, meat-base d, rice-dressing mix was strongly associated with illness. Nineteen patient isolates, six company/grocery store isolates cultured from the rice-dressi ng mix, and one environmental isolate from a pump in the production line we re of an identical outbreak strain of Salmonella Infantis characterized by pulsed-field gel electrophoresis. In the production line, cooked rice-dress ing mix tested negative for S. Infantis before and positive after contact w ith the contaminated pump. The dressing-mix had an estimated 200 colony-for ming units of salmonella per gram of product, and > 180 000 pounds were dis tributed in 9 states for greater than or equal to 2 months before contamina tion was recognized. Food manufacturers should be required to use systemati c, hazard analysis critical control point risk management practices for all processed meat products, validated by periodic microbiologic monitoring of the end product.