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Updated: Sep 23, 2025
Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce
Published on: October 18, 2010
Rapid qualitative and quantitative detection of Salmonella typhimurium using a single-step dual
Yanli Fu1, Jia Wei2, Shuo Yao1
1School of Public Health, Jilin University, Changchun, 130021, People's Republic of China.
Abstract:
A dual-signal photometric/fluorometric assay was established for rapid, qualitative, and quantitative detection of Salmonella typhimurium (S. typhimurium). This method was composed of two parts: (1) a single-step photometric (SSC) assay containing gold nanoparticles (AuNPs), poly-diallyldimethylammonium chloride (PDDA), and S. typhimurium-specific aptamer, and (2) a fluorescence (FL) assay containing carboxyl-modified CdSe/ZnS quantum dots (QDs-COOH). Users just need to drop samples contaminated with S. typhimurium into SSC assay; the apparent color change from red to blue can be observed in a short time (20 min). A smartphone app was developed to read the semiquantitative result. By subsequently adding one drop of FL assay into the reaction mixture, the generated fluorescence intensity reflected the concentration of S. typhimurium. The naked eye limit of detection (LOD) and fluorescent LOD were 103 cfu/mL and 10 cfu/mL, respectively. This method exhibited good selectivity. The reliability and practicability were verified by testing contaminated food, drinking water, and pets' urine.
