Liquid Core Waveguide Spectroscopy Combined with Magnetic Microparticle ELISA for Highly Sensitive Detection of Salmonella in Eggs

Non-Technical Summary:<br/>
Food borne microbial pathogens are the leading threat to a safe food supply. Present methods for detecting microbial pathogens in food safety inspection programs involve long-time enrichment processes due to the limited sensitivity of detection technologies. The long waiting -time feature adds a high cost to agricultural products related to storage and freezing, and causes deterioration of food quality. Therefore, there is a pressing need for quick detection technologies in food safety inspection programs. The goal of this project is to develop an immunomagnetic separation (IMS) enzyme-linked immunosorbent assay (ELISA) liquid core waveguide (LCW)spectrometric method for field applicaions of direct dection of Salmonella bacteria in egg samples. The proposed technique integrates advanced biotechnologies and highly sensitive LCW spectroscopic tehcniques recently developed for detecting microbial food pathogens.
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Approach:<br/>
IMS and ELIZA will be integrated with LCW optical spectroscopy. The procedure of proposed analytical method is as follows: Egg samples diluted with a buffered solution is first mixed with anti Salmonella antibody coated magnetic microparticles (MMP)in a beaker under vigorous stirring. The (MMP)suspended solution is then flowed through a specially designed flow-cell. A magnet is attached to a screw thred plug, which is screwed to the flow-cell wall for collecting the MMP. The MMP are then washed in a reactor with a buffered solution. an HRP-labeled anti Salmonella antibody solution is added to the reactor to label Samonella bacteria trapped to MMP surface. After washing MMP with a buffered solution again, a substrate solution for horseradish peroxidase (HRP) is added to the reactor. In each of these labeling, washing and substrate development processes, a MMP suspended solution is stirred, then, the magnet is used to separate MMP from solution. the developed substrate solution in the reactor is injected to a LCW for optical spectroscopic detection.