An investigation of an outbreak of Salmonella Newport infections linked to melons – United States, 2020

• Published in: Food control Vol. 152; p. 109833
• Main Authors: Jenkins, Erin, Gardenhire, Ifueko, Whitney, Brooke M., Martin, Krystalyn B., Schwensohn, Colin, Gieraltowski, Laura, Leeper, Molly M., McCurdy, Vivien, McClure, Monica, Wellman, Allison, Pightling, Arthur, Smith, Michelle, Swinford, Angela, Hainstock, Lisa, Crosby, Alvin J., Bazaco, Michael C., Viazis, Stelios
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2023
• Subjects: Foodborne illness outbreaks; Melons; Salmonella Newport; Foodborne illness outbreaks; Salmonella Newport; Melons
• ISSN: 0956-7135; 1873-7129
• DOI: 10.1016/j.foodcont.2023.109833

The United States are one of the world's leading consumers of melons. In 2020, the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state health and regulatory partners investigated an outbreak of Salmonella Newport infections linked to melons from southwest Indiana, resulting in 80 ill persons and 18 hospitalizations reported across 15 states. Epidemiologic and traceback data indicated melons as the vehicle for these infections, but the collinearity of melon varieties purchased and consumed together in combination with the traceback investigation that could not rule out either melon type, did not allow investigators to delineate whether the vehicle was cantaloupe alone or, both cantaloupe and watermelons. Analysis of traceback records for cantaloupe and/or watermelon exposures for 12 ill people indicated convergence on a grower in southwest Indiana which supplied cantaloupe to the nine of eleven points of service where ill people purchased cantaloupe; similar convergence was not observed for watermelon. While Salmonella isolates were recovered from environmental samples collected by FDA throughout the growing operation, they were not highly genetically related to the outbreak strain by whole genome sequencing analyses, i.e. greater than a 20 high quality single nucleotide polymorphisms difference. This outbreak illustrates the need for additional efforts to determine the source and extent of environmental contamination in the melon growing region of southwest Indiana and emphasizes the need for outreach and education efforts to help promote farm practices to reduce pathogen contamination of melons. •Federal and state partners investigated an outbreak of Salmonella Newport infections in which epidemiologic and traceback data indicated melons as the vehicle for the outbreak.•Traceback identified a grower in southwest Indiana for an on-farm investigation.•Salmonella isolates were recovered from samples from throughout the growing operation.•Recovered Salmonella isolates were not highly genetically related to the outbreak strain.•Outreach and education can promote farm practices to reduce contamination of melons there is need for research in the melon growing region of southwest Indiana.