1a. Objectives (from AD-416)
1. Develop useable technologies to rapidly and effectively concentrate viable target cells from various food matrices in a self-validating subsystem. 2. Develop, evaluate and adopt novel technologies for detection, identification, and quantification of viable and non-viable target microorganisms. Research areas to be addressed are biochip based technology, optical light scattering technology, fluorescence resonance energy transfer spatial technology, and fourier-transform infrared spectroscopy technology.
1b. Approach (from AD-416)
Develop rapid and affordable technologies for detection of harmful levels of biological and chemical food contaminants; to establish better methods of food sample preparation and contaminant separation procedures that can be used with different detection based technology platforms; to use detection systems, sample preparation and contaminant separations techniques to evaluate the efficacy of novel means of food protection; and to provide education, training, and technology transfer necessary for national implementation of these research programs.
3. Progress Report
The work at Purdue University combines food pathogen separation techniques and food pathogen detection platforms in an effort to detect pathogens more accurately and more rapidly. Continued progress is being made relative to pathogen target separation and recovery from foods. Filtration techniques can now separate organisms more easily from food matrices, so that appropriate cell levels can be delivered to different detection technologies. Cell concentration can be enhanced by over 1000 fold. As a result, many of the detection systems can now detect cell levels as low as 10 cells per gram or milliliter in the food. Relative to detection, the most significant progress has been made this year using light scattering techniques: BARDOT (BActerial Rapid Detection using Optical scattering Technology) and FTIR (Fourier Transform InfraRed) spectroscopy Light scattering, using BARDOT, has been expanded to detect over 20 different genera of bacteria from a wide variety of solid growth media. BARDOT instruments have been constructed and are currently being tested by laboratories associated with the food industry, USDA, CDC, and FDA. After the BARDOT system is evaluated later this year, it will be ready for use to perform microbial detection on a much larger scale. FTIR is nearly perfected in detection of viable vs. non-viable cells (99.9%) and can be used to differentiate many bacterial species quickly and inexpensively. A large spectral library consisting of Raman and FTIR fingerprints for E. coli, Salmonella, Listeria, Shigella, and Staphylococcus was completed. Progress was monitored by monthly meetings in addition to phone calls, emails and/or conference calls as needed.