A novel nanoparticle-based fluorescent sandwich immunoassay for specific detection of Salmonella Typhimurium

• Published in: International journal of food microbiology 2024-03, Vol.413, p.110593-110593, Article 110593
• Main Authors: Dou, Xuechen, Zhang, Zhiwei, Li, Chao, Du, Yaohua, Tian, Feng
• Format: Article
• Language: English
• Subjects: biotin; detection limit; fluorescence; Fluorescent nanoparticles; food microbiology; human health; immunoassays; microparticles; milk; particle size; quantitative analysis; Rapid detection; rapid methods; Salmonella Typhimurium; Single-bacterium counting method; Streptavidin
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2024.110593

The diseases caused by foodborne pathogens have a serious impact on human health and social stability. Conventional detection methods can involve long assay times and complex pretreatment steps, making them unsuitable for rapid, large-scale analysis of food samples. We constructed a novel nano-fluorescence sandwich immunosorbent immunoassay (nano-FSIA) to rapidly detect Salmonella Typhimurium in food, based on strong covalent binding between streptavidin and biotin. We used antibodies coupled to large particle-size fluorescent microspheres as fluorescent probes for direct quantitative analysis of S. typhimurium in milk. The optimized parameters were determined, and specificity and sensitivity were validated in phosphate-buffered saline (PBS) and milk. The results demonstrated a wide dynamic detection range for S. typhimurium (103–108 colony forming units [CFU]/mL), with the limit of detection in PBS and milk at 234 and 346 CFU/mL, respectively. The results of nano-FSIA were consistent with those of plate counts and enzyme-linked immunosorbent assays, providing an effective and promising single-bacterium counting method for the rapid detection of Salmonella. •A particle-based immunofluorescence (IF) method was developed for S. typhimurium.•Immunofluorescence sensors are easy to use and assay time