APPLICATION OF GENE AMPLIFICATION IN CONJUNCTION WITH A HYBRIDIZATIONSENSOR FOR RAPID DETECTION OF SALMONELLA SPP. AND FECAL CONTAMINATIONINDICATORS IN ANIMAL FEEDS

The rapid detection of pathogenic microbial species in feed is of para mount importance considering its implications for animal production an d food safety. To demonstrate the feasibility of rapidly detecting Sal monella spp. and fecal pollution microbial indicators in feed using ge ne amplification protocols, commercial and mixed feed samples were ino culated with two levels of a marker strain of S. typhimurium. Liquid e xtracts of the feed samples were used as templates in gene amplificati on reactions to amplify sequences associated with fecal contamination indicators. The sequence specificity of the amplification products (am plicons) were confirmed using biotin and fluorescein labeled probes in a novel dual probe based hybridization sensor. Using the combination of gene amplification and the hybridization sensor, the presence of se quences associated with fecal contamination were detected in 15 differ ent feed matrices without employing preenrichment steps. Using this de tection methodology, fecal pollution can be confirmed in feed at natur ally occurring concentrations. The study demonstrates that it is possi ble to rapidly detect and confirm the presence of pathogenic bacterial genera in feed matrices by combining robust gene amplification reacti ons with appropriate post amplification detection systems.