Evaluation of immunomagnetic separation for the improvement of Salmonella detection in aquatic environment

Abstract

This study compares various immunomagnetic separation (IMS) protocols. The average recovery efficiency of IMS for different Salmonella concentrations (between 102 and 105 CFU/ml) was 53.5 ± 12.9 % (n = 24). When turbidity was less than 1,000 NTU, altering the debris ratio of water samples produced no significant changes in the recovery efficiency of IMS. Prolonging the incubation time or increasing the amount of immunomagnetic beads increased the recovery efficiency of IMS. This study also compares processes in which water samples were filtered, eluted/concentrated, and then processed by the IMS and non-IMS methods before PCR. Results indicate that IMS can effectively eliminate these inhibitors prior to polymerase chain reaction (PCR). The detection limit of Salmonella analysis process with IMS separation before enrichment was superior to IMS separation after enrichment. The proposed Salmonella analysis process, which included IMS to concentrate and purify the Salmonella, improves the sensitivity and the detection efficiency of the entire analysis process.