Assessment of the Prevalence of Presumptive Bacillus cereus, Vibrio spp., and Extended-Spectrum β-Lactamase (ESBL)-Producing Enterobacterales in Sushi Products Collected From Swiss Retail Stores

Background: Sushi is a popular Japanese dish made from acidified cooked rice, seafood, and other ingredients. In this study we aimed to assess the microbiological quality of sushi products collected at retail level in Switzerland for the presence of Bacillus (B.) cereus group members, extended-spectrum β-lactamase (ESBL)-producing Enterobacterales and Vibrio spp. Methods: Between January and February 2024, a total of 52 sushi products were randomly collected from five different retail stores and from one restaurant. The collection included boxes of assorted sushi and various sushi snacks from 13 different brands. The products were produced for the most part in Switzerland, Poland, and Germany. Results: In a quantitative analysis, one out of 52 products (2%) tested positive for B. cereus group members, with a colony count of 100 CFU/g. After enrichment, B. cereus group members were isolated from six (11%) of the products. Five products (10%) tested positive for ESBL-producing Enterobacterales. All ESBL-producers were Serratia fonticola which harbor a chromosomally encoded fonA ESBL gene. Vibrio spp. were not detected in any of the 52 products. Conclusions: This study attests to a good microbiological quality of the collected samples with regard to the tested parameters.