FDA Releases Investigation Report for Largest Salmonella Outbreak In Over A Decade
The US Food and Drug Administration (FDA) released the investigation report for the Summer 2020 Salmonella Newport Outbreak on March 13, 2021. The report provides an executive summary of the outbreak explaining the processes and conclusions of the investigation.
Beginning in June through October 2020, Federal and state health officials investigated the Salmonella Newport foodborne outbreak connected with the consumption of Thompson International Inc. red onions sourced from farms in Southern San Joaquin Valley and Imperial Valley in California. This is the largest Salmonella outbreak in over a decade, resulting in 1,127 domestic illnesses and 515 Canadian illnesses. This outbreak is also noteworthy as whole red onions have never been associated as the carrier of a foodborne illness outbreak before.
When reported cases of illness attributed to the consumption of Thompson International red onions began emerging in the US and Canada, federal and state health agencies began investigating the origin of the Outbreak at farms in Southern San Joaquin Valley and Imperial Valley, California. Initial samples from ill persons revealed the presence of Salmonella Newport. Subsequent testing at and around the farms which supply red onions to Thompson International in these regions was conducted. While none of the 2,000 subsamples collected matched the specific Salmonella Newport Outbreak strain (tested through Whole Genome Sequencing analysis), 11 subsamples (10 water and 1 sediment) revealed the presence of three different geneotypic strains of Salmonella Newport near growing fields.
Although the specific source of the Salmonella Newport strain which caused the Outbreak was unable to be identified, health officials hypothesize that a contaminated irrigation system used for a growing field in Holtville, California may have been the initial cause of the outbreak. Other potential causes or propagators may have been an adjacent sheep grazing field and animal intrusion. Furthermore, investigation of Thompson International’s packaging practices revealed a need for tightened contamination prevention strategies, such as the prevention of animal and pest intrusion and better maintenance and cleaning of food contact surfaces. Thompson International Inc. has cooperated with the investigation and guidance of the FDA in addressing these issues.
This outbreak points to the interconnected nature of our environment and the need for a sense of the shared responsibility amongst the whole agricultural community (livestock owners and produce farmers), as well as the companies handling and packaging food, in order to grow/raise, process, package, and deliver food safely to the consumer.