Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2006
Publication Date: 5/21/2006
Citation: Huff, K.R., Banada, P.P., Bae, E., Bayraktar, B., Rajwa, B., Robinson, J.P., Hirleman, E.D., Richards, G.P., Bhunia, A.K. 2006. Detection and identification of foodborne pathogens to genus and species levels using a noninvasive modified light scatterometer - bardot. American Society for Microbiology. P-075. Interpretive Summary:
Technical Abstract: Specific and rapid detection of pathogens in clinical, food, water or air samples, has proven to be a very difficult task but is essential for developing counter measures against food safety and biosecurity. Optical light scattering has been widely used for characterizing microorganisms in suspensions, but success has been limited. In this study, an improved light scatterometer - Bacteria Rapid Detection using Optical Scattering Technology (BARDOT), as a non-invasive optical light sensor has been developed for bacterial colony identification on a nutrient agar plate. Bacterial colonies of Listeria, Salmonella, Vibrio, Enterobacter, Enterococcus, Escherichia, and Bacillus were tested using BARDOT system. Purity of each bacterial culture was tested and identified using Gram staining, CAMP test (for Listeria), PCR and ribotyping. The cultures were grown in BHI broth, serially diluted and spread plated to obtain ~20-30 colonies/plate. The colonies were allowed to grow to ~2 mm (12-36 h at 37 C). Images of one hundred colonies from each culture were captured using the BARDOT system and were analyzed by extracting features using Zernike moments and grouped using principle component analysis (PCA) and K-means clustering. All the cultures mentioned above gave unique light scattering patterns. Each image had a characteristic circular ring pattern or spike like structures or a fuzzy uneven appearance differing for each bacterial species. The image patterns for each genus and species within the genus were very distinct and even could be easily identified by untrained human eyes. BARDOT has proven to be an elegant powerful tool in rapid detection and identification of bacterial colonies grown on solid agar surfaces in 5 min.