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The present invention is directed to satisfying the need to detect microbial contamination of food products. The described bioseparator/bioreactor coupled with an optical/electrochemical biosensor was able to specifically detect E. coli O157:H7 from 8.8 x 10^1 to 8.8 x 10^6 CFU/ml in 2.5 hours without any enrichment. Using this invention, concentrations of S. Typhimurium ranging from 8.6 x 10^2 to 8.6 x 10^6 CFU/ml in pure culture were detected in 2 hours without any enrichment. The invention may also be used for the detection of S. Seftenberg, which has the same sensitivity as S. Typhimurium. Other pathogens such as L. monocytogenes and S. Heidleberg did not interfere with the detection. The optimum inner diameter of the 25 cm long column for the detection of E. coli O157:H7 is 250 micro m. The detection limit for other microbial pathogens may be controlled by changing the length of capillary columns, using higher concentration of the labeled antibodies, altering the flow rate and concentration of the substrate, and increasing the reaction temperature to 37 degree C.


Biological and Agricultural Engineering

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Board of Trustees of the University of Arkansas (Little Rock, AR)


STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with Government support under the terms of Grant Nos. 2001-35201-10056 and 2001-34211-10288 awarded by the USDA/NRI and USDA/FSC. The Government has certain rights in this invention.

Yanbin Li, Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR