Mining and evaluation of new specific molecular targets for the PCR detection of Salmonella spp. genome.

The purpose of this study is to find new molecular targets for the detection of Salmonella. With the online BLAST Program, we compared homology of genomic sequences and specificity in GenBank among Salmonella serovars and non-Salmonella strains and found 98 Salmonella specific target sequences. We selected 33 target sequences of Gene ID from 3335000 to 3337003 for the specificity evaluation, and finally 8 specific fragments screened out, they are 3334138, 3335583, 3335471, 3335211, 3335068, 3336466, 3336736 and 3336998. Primer SC8 of gene 3335583 and SC9 of gene 3335471 were the best in specificity and sensitivity among these primers. The detection sensitivity of Primer SC9 was 1.23 fg/μl for DNA templates and 720 cfu/ml for whole cells, while primer SC8's was 12.3 fg/μl and 720 cfu/ml, respectively. Salmonella could be detected successfully by the PCR method developed in this study after 8 h enrichment when the milk samples were artificially contaminated by this organism at 7 cfu per 10 ml milk.