The Magnetic Immuno Polymerase Chain Reaction Assay for Detection of Salmonella from Food and Fecal Samples

The present study was performed to isolate Salmonella by plating the bead-bacteria complexes on DHL agar after immunomagnetic separation (IMS) from food and fecal samples contaminated artificially at 1 to 103 cfu/ml, and then to detect Salmonella by polymerase chain reaction (PCR) assay. With IMS, it was possible to collect Salmonella from the samples at 1 cfu /ml. Even if colonies other than Salmonella developed on the selective agar plate, only Salmonella was detected by the PCR assay using two pairs of primers for the Salmonella invA and stn genes. Also, Salmonella was completely detected within 24 h from eggs contaminated naturally with Salmonella O9 and from diarrheal stool samples of patients with Salmonella O9 or O16. This combination of IMS and PCR seems to be a useful method for rapid and sensitive detection of Salmonella in food products and fecal specimens.