STTR Phase II: Early Detection and Identification of Individual Pathogenic Microorganisms in Food with a Flow Cytometer

Softray Incorporated, Laramie WY

Investigators

Abstract

This Small Business Technology Transfer Phase II Project will demonstrate the real-time detection of single foodborne pathogenic bacteria in a real-world operating environment. SoftRay demonstrated an innovative technique to detect pathogenic microorganisms in Phase I, based on laser-induced fluorescence coupled with flow cytometry. The Phase I research showed conclusively that this approach is feasible, and that the technique has key advantages over current alternatives including it is: 1) capable of detecting single microorganisms (techniques other than immunofluorescent flow cytometry or immunofluorescent microscopic imaging require in excess of 104 microorganisms), 2) able to completely examine a large volume of food or water in real time, 3) intrinsically automatic, and 4) sensitive only to the selected bacteria or viruses. In Phase II, SoftRay will demonstrate a lost-cost, self-contained prototype system for the detection of pathogenic microorganisms in food or water, including E. coli O157:H7 on beef. This innovative technique is based on laser-induced fluorescence in which a stream of solution containing the microorganisms is labeled with fluorescent probes and is then illuminated with a laser diode (commonly called flow cytometry). The resulting fluorescence is detected with a CCD imager using a novel time-integration scheme. The proposed device will use a simple optical configuration and a laser diode to provide a low-cost, rugged, small, lightweight package that can be used to detect specific, individual bacteria in real time. Key technology objective is to develop a pathogenic bacteria detection technique that can analyze 1 ml of fluid for selected pathogens in less than 1 minute, to a sensitivity of less than 10 pathogenic microorganisms per ml. The result of the Phase I and II project will be the demonstration of a prototype sensor capable of individual microorganism detection of unprecedented sensitivity, selectivity, and speed. This will enable rapid detection of individual specific pathogenic microorganisms in a wide array of applications, including: food processing inspection, clinical applications (such as detection of tuberculosis in sputum), biological warfare defense, and many other situations where single microorganism detection is required. The technique can also be used to detect small numbers of molecules, including explosives and groundwater contaminates.