As part of our investigation on behalf of several clients sickened in this outbreak, we were provided the report by the Minnesota Department of Health (MDH). The significant parts are below as is the full report.
On October 16, 2007 the Minnesota Department of Health (MDH) Public Health Laboratory (PHL) identified seven case isolates of Salmonella Typhimurium with indistinguishable pulsed-field gel electrophoresis patterns (subtype designated TM5b) through routine surveillance. One of the first cases interviewed reported eating at a Quiznos restaurant in Rochester on October 3. The same day, the MDH foodborne illness hotline received a complaint of gastrointestinal illness from a patron who had eaten at the same Quiznos restaurant on October 4. MDH and Olmstead County Public Health Services (OCPHS) initiated an outbreak investigation on October 16.
This was an outbreak of S. Typhimurium infections associated with consumption of tomatoes at a Quiznos restaurant. The tomatoes were likely already contaminated when they entered the restaurant. Based on case meal dates and produce receipt records, the most likely scenario is that the outbreak was due to second-use tomatoes that entered the restaurant on September 27. These tomatoes were stored at room temperature for ripening before being used around October 1. Any prior contamination could have amplified during this ripening period. Tomatoes used during the outbreak period were not available for testing.
Cross contamination of tomatoes from meat was ruled out as a cause of this outbreak, as Quiznos does not receive any raw meat products. Ill foodworkers were identified, including two that were confirmed with the outbreak type of S. Typhimurium; however, these foodworkers were likely victims of the outbreak rather than a source of Salmonella for patrons. Several patron cases reported meal dates prior to foodworker illness onset dates. In addition, handwashing, glove use, and ill employee exclusion policies and practices were found to be appropriate by OCPHS.