ABSTRACT
Recently, two rapid methods using bacteria-specific DNA or oligonucleotide fragments have been developed for the detection of pathogenic bacteria in food samples. These methods are the DNA-DNA hybridization method, using DNA or oligonucleotide probes, and the polymerase chain reaction (PCR) method, using pairs of oligonucleotide primers. This chapter shows the methods to isolate the salmonella-specific DNA fragment as well as the designation of oligonucleotide probes and PCR primers specific for the detection of all salmonellae serotypes in foods. Relative to the detection sensitivity for such PCR methods, the DNA from one cell could be detected unambiguously. Therefore, in using the PCR method for detection of Salmonella food samples could be used directly for examination, without any enrichment step; thereby considerably shortening the total time required to complete the detection. Although DNA hybridization is a rapid method for bacterial detection, the method is not reliable for some food samples if a suitable enrichment step was not performed before the hybridization step.
