title: Digoxigenin-labeled probe-based colony blotting assay for rapid quantification of Salmonella serovars in seafood and water.
abstract: A non-radio-labeled probe-based detection method was developed for rapid enumeration of Salmonella in seafood and water samples. A Salmonella-specific invA gene probe was developed using a digoxigenin-based non-radio labeling assay, which was evaluated with naturally contaminated seafood and water samples. The probe-based technique was further compared with the quantitative PCR assay. The method was specific for detection of different Salmonella serovars without any nonspecific hybridization with other Salmonella-related Enterobacteriaceae. The optimum labeling efficiency was determined for the labeled probe, and 10 pg/microL probe concentration was observed to be most efficient for detection of Salmonella colonies on nylon membrane. Quantification of Salmonella in naturally contaminated seafood and water samples (n = 21) was in the range 10-10(2) CFU/mL. The assay successfully quantified Salmonella in spiked seafood and water samples in the presence of background flora, and the entire assay was completed within 48 h. The probe-based assay was further evaluated with real-time PCR, and results showed that the assay was comparable to real-time PCR assay. Thus, this probe-based assay can be a rapid, useful, and alternative technique for quantitative detection of Salmonella in food, feed, and water samples.
authors: Central Institute of Fisheries Technology, Microbiology, Fermentation and Biotechnology Division, Cochin, India. rakeshcift@gmail.com
authors: Rakesh
authors: R
authors: Kumar
authors: K V
authors: KV
authors: Lalitha
mesh_terms: D058491:Bacterial Load; D015169:Colony Count, Microbial; D015342:DNA Probes; D004076:Digoxigenin; D005516:Food Microbiology / Q000379:methods*; D006824:Hybridization, Genetic; D007202:Indicators and Reagents; D016133:Polymerase Chain Reaction; D012475:Salmonella / Q000737:chemistry*; D017747:Seafood / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D015342:DNA Probes; D007202:Indicators and Reagents; D004076:Digoxigenin