FIG. 3.

Tape-FISH combined with liquid surface miniculture for rapid detection of S. enterica serovar Typhimurium on tomatoes via flow cytometry. Adhesive tape was used to remove serovar Typhimurium from tomato surfaces inoculated with 10³ cells cm⁻². As described for Fig. 2B, cell-charged tapes were mounted face-up on microscope slides, and perfusion chambers were placed on top of the tape and filled with nonselective broths. Liquid surface minicultures were incubated for 5 h, mixed via up-and-down pipetting using gel loading tips, processed for FISH, and then analyzed via flow cytometry. When TSB was used, it was possible to detect Salmonella directly from tapes (0 h, TSB). Despite a lack of visible turbidity, substantial enrichment was possible after only 5 h of nonselective pre-enrichment in TSB. These data show the utility of FISH and flow cytometry in combination with adhesive-tape-based sampling for the rapid detection of Salmonella on contaminated tomatoes.