An Investigation of an Outbreak of Salmonella Newport Infections Linked to Melons from Southwest Indiana-United States, 2023.

Abstract

The Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state health and regulatory partners have investigated outbreaks of Salmonella enterica serovar Newport and Typhimurium infections in 2012, 2020, 2022, and 2023 linked to cantaloupes and/or watermelons from Southwest Indiana. In 2023, an outbreak of Salmonella Newport infections included 11 ill people and five hospitalizations reported in six states. The FDA and CDC collaborated with state partners to investigate the outbreak. The traceback investigation did not identify a single point of convergence for cantaloupe or watermelon. Products and environmental samples collected by the FDA and state partners from farms, public land, distributors, and points of service yielded isolates of multiple Salmonella serovars, including Salmonella Typhimurium and Salmonella Newport, that matched by whole genome sequencing to the 2020, 2022, and 2023 outbreak strains. Due to limitations with the traceback investigation and lack of convergence, a specific type of melon or source of contamination was not identified. However, the laboratory findings and historical outbreak information provided additional evidence to support a finding of ongoing contamination issues for cantaloupes and watermelons grown in Southwest Indiana. This is the fourth outbreak of salmonellosis confirmed to be linked to cantaloupes and/or watermelons from this area since 2012. These outbreaks of reoccurring and persisting strains of Salmonella illustrate the urgent need to determine the source, pathway, and extent of environmental contamination in the melon-growing region of Southwest Indiana and for outreach and education to help promote practices to reduce the contamination of melons.