Salmonella, a highly virulent food-borne pathogen transmitted through food, can cause severe infectious diseases in a large number of people through a single outbreak, due to its low infective doses. In this study, a flow cytometry (FCM)-based method was developed for the rapid detection of single viable Salmonella cells with dual staining of fluorescein isothiocyanate (FITC)-labeled anti-Salmonella antibody and propidium iodide (PI) dyes. The FCM-based method includes 6 h of pre-enrichment, 40 min of target cell isolation, and 20 min of dual staining and FCM analysis. The developed method demonstrated high specificity for the detection of 23 Salmonella strains and 22 food-borne pathogenic non-Salmonella strains. Furthermore, the analyses of 30 samples of milk powder artificially contaminated with single Salmonella cells, 123 samples of retail milk powder, and 6 samples of Salmonella-positive milk powder were performed by the FCM-based as well as traditional plate-based methods for testing the efficiency of the methods. The two methods yielded similar results for the detection of pathogens in all milk powder samples. In conclusion, the developed FCM-based method was found to be efficient in detecting single viable Salmonella cells in milk powder within 7 h. The proposed dual-color FITC assay combined with pre-enrichment offers a great potential for the rapid and sensitive detection of other pathogens in dairy products.

中文翻译：

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奶粉中单个活沙门氏菌细胞的快速流式细胞术检测。

沙门氏菌是一种通过食物传播的高毒力食源性病原体，由于其感染剂量低，可通过一次暴发在大量人群中引起严重的传染病。在本研究中，开发了一种基于流式细胞术 (FCM) 的方法，用于通过异硫氰酸荧光素 (FITC) 标记的抗沙门氏菌抗体和碘化丙啶 (PI) 染料的双重染色快速检测单个活沙门氏菌细胞。基于 FCM 的方法包括 6 小时的预富集、40 分钟的靶细胞分离和 20 分钟的双染色和 FCM 分析。开发的方法显示出检测 23 种沙门氏菌菌株和 22 种食源性致病性非沙门氏菌的高特异性菌株。此外，对人工污染单个沙门氏菌细胞的30份奶粉样品、123份零售奶粉样品和6份沙门氏菌阳性奶粉样品进行了基于FCM和传统平板检测方法的分析。方法的效率。这两种方法在检测所有奶粉样品中的病原体方面产生了相似的结果。总之，发现开发的基于 FCM 的方法可有效地在7 小时内检测奶粉中的单个活沙门氏菌细胞。拟议的双色 FITC 检测与预富集相结合，为快速、灵敏地检测乳制品中的其他病原体提供了巨大的潜力。