Comparative Study of Colorimetric DNA Hybridization Method and Conventional Culture Procedure for Detection of Salmonella in Foods

Abstract

A second generation nucleic acid hybridization assay has been developed and evaluated against the conventional culture method for detection of salmonellae In foods. The assay Involves a liquid hybridization with Sa/mone/fo-speclflc oligonucleotide probes, capture of probe:target hybrids onto a solid support (plastic dipstick), and a colorimetric end point detection. The assay can be completed In 2.5 h, following approximately 44 h of culture enrichment. One thousand samples representing 20 food types were analyzed in parallel by both methods. Samples Included unlnoculated test product, and product Inoculated with Salmonella at 2 levels. Eighteen Salmonella serotypes were used as Inocula. The data demonstrate that the colorlmetric hybridization method and the conventional culture method are equivalent In their ability to detect Salmonella contamination of foods.

Development of a Colorimetric, Second Generation Nucleic Acid Hybridization Method For Detection of Salmonella in Foods and a Comparison With Conventional Culture Procedure

“…In light of these restrictions, a calorimetric, second generation nucleic acid hybridization-based assay has recently been developed (cDNAH). Following recent testing in comparative and collaborative studies (Chan et al, 1990;Curiale et al, 1990) it has been granted Interim Official First Action status by the AOAC. This assay relies on detection of Salmonella ribosomal RNA (rRNA), the nucleic acid component conserved during evolution of the ribosome.…”

DNA-based diagnostic tests for Salmonella species targeting agfA, the structural gene for thin, aggregative fimbriae

“…The utilization of an agfA nucleotide probe in combination with automatable HGMF technology (40) provides a valuable new diagnostic format for Salmonella spp. In comparison with other Salmonella DNA probes (5,6,14,16,34,43,48), the agfA probe demonstrated excellent inclusivity and exclusivity properties representative of the high degree of conservation of agfA among Salmonella serovars. Under appropriately stringent conditions, we detected no hybridization of a 333-bp region of agfA to the vast majority (81%) of non-Salmonella members of the family Enterobacteriaceae represented on the HGMF panels, including almost all strains of E. coli, Citrobacter, and Enterobacter and all strains of Shigella, Serratia, and Yersinia.…”

Comparison of the Vitek, API 20E and Gene‐trak® systems for the identification of Yersinia enterocolitica

“…The assay has been used to detect Salmonella spp. (Chan et al 1990;Curiale et al 1990;Wilson et al 1990;Mozola et al 199 l), Escherichia coli and Staphylococcus aureus (Kneifel et al 1992) and Listeria spp. (King et al 1989).…”