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Flow‐through imaging cytometry for characterization of Salmonella subpopulations in alfalfa sprouts, a complex food system
Author(s) -
Bisha Bledar,
BrehmStecher Byron F.
Publication year - 2009
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.200800360
Subject(s) - salmonella , flow cytometry , biology , fish <actinopterygii> , fluorescence in situ hybridization , in situ hybridization , microbiology and biotechnology , bacteria , genetics , gene , gene expression , chromosome , fishery
We recently developed an approach combining fluorescence in situ hybridization (FISH) and flow cytometry for detecting low levels of Salmonella spp. (∼10 3 cells/mL sprout wash) against high levels of naturally occurring sprout flora (∼10 7 –10 8 CFU/g sprouts). Although this “FISH and flow” approach provided rapid presence/absence testing for Salmonella in this complex food system, it was not capable of more nuanced tasks, such as probing the phenotypic complexity of the microbes present in sprouts or determining the physical interactions of Salmonella with these microbes, or with sprout debris. In the present study, we have combined rapid FISH‐based labeling of Salmonella spp. in sprout washes with flow‐through imaging cytometry (FT‐IC), using the ImageStream ® 100, a commercial FT‐IC instrument. This approach enables image‐based characterization of various subpopulations of interest occurring within these samples. Here, we demonstrate the ability of FT‐IC to unambiguously identify cells, cell aggregates and other events within these subpopulations based on both cell morphology and hybridization status after reaction with a Salmonella ‐targeted probe cocktail. Our ability to directly explore the nature of these events expands the layers of information possible from cytometric analyses of these complex samples and clearly demonstrates that “a picture is worth a thousand dots”.