Colonization and Internalization ofSalmonella entericaand Its Prevalence in Cucumber Plants

Consumption of cucumbers (Cucumis sativusvar.sativus) has been linked to several foodborne outbreaks involvingSalmonella enterica. The purpose of this work was to investigate the efficiency of colonization and internalization ofS. entericainto cucumber plants by various routes of contamination. Produce-associated outbreak strains ofSalmonella(a cocktail of serovars Javiana, Montevideo, Newport, Poona, and Typhimurium) were introduced to three cultivars of cucumber plants (two slicing cultivars and one pickling) via blossoms (ca. 6.4 log(10)CFU/blossom, 4.5 log(10)CFU/blossom, or 2.5 log(10)CFU/blossom) or soil (ca. 8.3 log(10)CFU/root zone) and were analyzed for prevalence ofSalmonellacontamination (internal and external) and serovar predominance in fruit and stems. Of the total slicing fruit harvested fromSalmonella-inoculated blossoms (ca. 6.4, 4.5, or 2.5 log(10)CFU/blossom), 83.9% (47/56), 81.4% (48/59) or 71.2% (84/118) were found colonized and 67.9% (38/56), 35.6% (21/59) or 22.0% (26/118) hadSalmonellainternalized into the fruit, respectively.S.Poona was the most prevalent serovar isolated on or in cucumber fruits at all inoculation levels. When soil was inoculated at 1 day post-transplant (dpt), 8% (10/120) of the plants were shown to translocateSalmonellato the lower stem 7 days post-inoculation (dpi). Results identified blossoms as an important route by whichSalmonellainternalized at a high percentage into cucumbers, andS.Poona, the same strain isolated from the 2015 outbreak of cucumbers imported from Mexico, was shown to be well-adapted to the blossom niche.