Epidemiologic evidence indicates Persian cucumbers as the source of Salmonella Oslo infections in this outbreak sold at an unnamed grocery chain. This is the fourth Salmonella outbreak since 2013 associated with cucumbers, with over 1,200 illnesses and 260 hospitalizations included in the previous three outbreaks. Two of these outbreaks were caused by cucumbers sourced from Mexico, whereas the other outbreak identified cucumbers sourced from Maryland as a major cause of illnesses.
State and local public health officials in Minnesota and Michigan initiated an investigation when four persons with Salmonella Oslo infections were identified. A case was defined as infection with Salmonella Oslo with PFGE pattern OSLX01.0090 (the outbreak strain) in a person with illness onset occurring during March 21–April 9, 2016.
FDA, the Canadian Food Inspection Agency, and officials in Minnesota, Massachusetts, and Michigan collaborated to conduct an informational traceback investigation from retail establishments in these states to identify the source of the cucumbers. The investigation identified two Canadian Persian cucumber suppliers during the timeframe of interest, but a single grower was not identified. Growers who could have supplied these cucumbers were located in Canada, Mexico, and the Dominican Republic.