[Evaluation of new specific molecular targets for the PCR detection of Salmonella spp. in foods].
OBJECTIVE
The purpose of this study is to find new molecular targets for the detection of Salmonella.


METHODS
Homology comparison of genomic sequences in GenBank among Salmonella serovars and the specificity comparison among Salmonella and non-Salmonella strains were done with the BLAST (Basic Local Alignment Search Tool Program). We randomly selected 15 target sequences to design and synthesize 27 sets of primers for the evaluation of specificity and sensitivity and development of PCR methods.


RESULTS
Primer FS23 was the best in specificity and sensitivity among these 27 sets of primers. The 44 Salmonella strains produced a specific 492-bp amplification band, whereas 22 non-Salmonella strains did not using primer FS23 for PCR detection. The detection sensitivity of FS23 was 11.9 fg/microL for DNA templates and 4.9 x 10(2) cfu/mL for whole cells. Salmonella could be detected successfully by the PCR method developed in this study after 5 h enrichment when the milk samples were artificially contaminated by this organism at 100 cfu/25 mL.


CONCLUSIONS
The sequences against FS23 is a new and excellent molecular target for the detection of Salmonella. The FS23-based PCR assay is sensitive and specific, and can be used for rapid detection of Salmonella in foods.
Xiang
Xuefei
X
Department of Food Science and Bor Luh Food Safety Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. xiangxf@sjtu.edu.cn
Liu
Bin
B
Zhang
Lida
L
Shi
Xianming
X
D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D016133:Polymerase Chain Reaction; D012475:Salmonella / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013997:Time Factors
D017931:DNA Primers; D004269:DNA, Bacterial