Recent foodborne outbreaks in the United States linked to atypical vehicles - lessons learned

The past decade has seen atypical vehicles linked to foodborne outbreaks in the United States, including low moisture foods, frozen foods, and certain produce commodities which were not or rarely associated with outbreaks before. We reviewed selected recent outbreaks involving Salmonella, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes. Recognition of these outbreaks was partially due to improvements in outbreak response and surveillance, partially attributable to whole genome sequencing and related tools. Depending on the pathogen and vehicle, the contamination events leading to these outbreaks could occur before, during, and after food processing. Important data for root cause analyses are not always available because of inadequate traceability records or sampling throughout production chains, and challenges in detecting low levels of potentially injured pathogens heterogeneously distributed in foods. Further understanding of pathogen behaviors in these foods will enable better risk assessments and improve pathogen control strategies.