title: 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.
abstract: 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.
authors.affiliation: Department of Food Science, National Chung-Hsing University, Taichung, Taiwan, ROC.
authors.forename: Tasi-Hsin
authors.initials: TH
authors.lastname: Chiu
authors.forename: Tong-Rong
authors.initials: TR
authors.lastname: Chen
authors.forename: Wen-Zhe
authors.initials: WZ
authors.lastname: Hwang
authors.forename: Hau-Yang
authors.initials: HY
authors.lastname: Tsen
mesh_terms: 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
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S