An Optical biosensor platform to detect E.coli from animal feed

The average mortality rate of calves in the Rep. Korea, Europe, and North America was reported as 5.7~10. 7%, 2.6 ~ 7% and 5.6 ~ 9.4%, respectively. Among these ratios, almost 68% of calves died of gastrointestinal diseases wi th diarrhea and E. coli was the main cause. It is important to prescreen or detect E. coli on animal feed which is the ma jor pathway of its gastrointestinal infection. In this study, we developed an optical biosensor system to detect E. coli fro m animal feed by particle immunoassay method. The particle immunoassay measures light scatter intensity difference f rom antibody covered particles which agglutinate and increase size by the amount of antigen presence. E. coli antibody was immobilized on the surface of polymer particle and mixed with liquid extract from animal feed. The mixed solution was dropped on an optical scatter reader which consist with a 650nm laser module and a photodiode with the optimum angle. This sensor system is handheld and measured data can be delivered to a smartphone for data storage.