Although NASBA uses RNA as a target molecule for amplification, the nucleic acid amplification system cannot be used for differentiating viable and non-viable C. jejuni. It was shown that 16S rRNA, or the defined sequence within the 16S rRNA enclosed by the primer set applied, is fairly stable and resistant to heating at 100 degrees C. False-positive results can occur in case of direct NASBA detection of C. jejuni in foods. These false positive results due to amplification of RNA from dead cells were eliminated by prior selective enrichment in Preston medium for 24 h at 42 degrees C.