Abstract
In this study, an optimized method was developed to detect Salmonella by using immunomagnetic separation coupled with culture to selective agar (IMS/culture). To test the effectiveness of the methods and develop a rapid and sensitive detection procedure, direct culture, IMS/culture, and multiplex PCR (mPCR) were compared for the detection of Salmonella in 700 food samples. After selective enrichment, all samples were (I) subjected to direct culture, plated on xylose-lysine-tergitol 4 agar, and identified as Salmonella via biochemical and serological methods; (II) subjected to IMS then identified as (I); and (III) subjected to DNA extraction and mPCR analysis. A total of 83, 95, and 104 samples were found positive for Salmonella by direct culture, IMS/culture, and mPCR, respectively. Results suggested higher sensitivity in mPCR than in direct culture and IMS/culture methods. IMS/culture increased the detection rate of Salmonella and compared well with mPCR. This study demonstrated that the use of mPCR in pre-screening of samples and further identification by IMS/culture should enhance the positive identification and increase the number of isolates of Salmonella.
