Visual Detection of Salmonella in Food Using Saltatory Rolling Circle Amplification Combined with Gold Nanoparticles.

Salmonella is the main cause of human diarrhea worldwide, which seriously endangers human and animal health. Traditional detection methods are time -consuming and cumbersome, so it is of great significance to carry out rapid, simple and sensitive visual detection methods. In this paper, a probe that can bind to the target sequence was designed and combined with gold nanoparticles (AuNPs). The target sequence was amplified by saltatory rolling circle amplification (SRCA). After denaturation at high temperature, it became a single chain. After binding with the probe on gold nanoparticles, gold nanoparticles were released. Under the action of MgS04, the aggregation showed blue visible to the naked eye, which was judged to be positive and negative to be purple. Therefore, a simple, fast and sensitive visual detection method was established. The results showed that the method had good specificity and could distinguish 8 Salmonella positive and 8 non -Salmonella negative. The sensitivity of visual detection was 5.5 x10⁰ CFU/mL. The milk samples were artificially contaminated with Salmonella, and the detection limit was 3.7x10⁰ CFU/mL. Comparison with GB 4789.4-2016 method for detection of 50 actual samples, the sensitivity of this method was 100.00%, the specificity was 97.87%, and the coincidence rate was 98.00%. The SRCA-AuNPs visual detection method established in this paper has high application value, and the results are visible visually, which is suitable for on-site visual detection and grassroots units. [ABSTRACT FROM AUTHOR]