Sequencing of an internal transcribed spacer region of 16S-23S rRNA gene and designing of PCR primers for the detection of Salmonella spp. in food.
DNA sequences of an internal transcribed spacer (ITS) region for 40 Salmonella serovars were determined and compared with ITS sequences of Salmonella spp., and non-Salmonella spp. already available on the GenBank database. From such comparison, two Salmonella-specific ITS based PCR primers, ITSF and ITSR, were designed. When Salmonella strains with various serotypes were PCR assayed with primers ITSF/ITSR, all generated PCR products with molecular weight bands equal to 312 bp. On the other hand, 48 non-Salmonella isolates, including strains of Enterobacteriaceae and other food pathogens generated negative results. Detection limits of this PCR method was 1-9 CFU per assay. These PCR primers were used for the detection of Salmonella cells in artificially contaminated foods, including chicken meat and whole milk. The detection limit was 1-9 x 10(3) CFU per assay. With an 8-h enrichment step performed prior to the PCR assay, however, the detection limit became 1-9 CFU per gram of the food sample.
Chiu
Tasi-Hsin
TH
Department of Food Science, National Chung-Hsing University, Taichung, Taiwan, ROC.
Chen
Tong-Rong
TR
Hwang
Wen-Zhe
WZ
Tsen
Hau-Yang
HY
D000818:Animals; D002645:Chickens; D015169:Colony Count, Microbial; D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis*; D004275:DNA, Ribosomal / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012475:Salmonella / Q000235:genetics* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013045:Species Specificity
D017931:DNA Primers; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S