Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

A Bienzyme Electrochemical Biosensor Coupled with Immunomagnetic Separation for Rapid Detection of Escherichia coli O157:H7 in Food Samples

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Paper number  017048,  2001 ASAE Annual Meeting. (doi: 10.13031/2013.4433) @2001
Authors:   Chuanmin Ruan, Hong Wang, and Yanbin Li
Keywords:   Biosensor, foodborne pathogens, enzyme electrode, flow injection, immunomagnetic separation

A biosensing system, including an immunomagnetic separation (IMS), a flow injection and a bienzyme electrode, was developed for rapid detection of Escherichia coli O157:H7 in food samples. Samples inoculated with E. coli O157:H7 were mixed simultaneously with magnetic beads coated with anti-E. coli antibodies and alkaline phosphatase labeled anti-E. coli (APLAE) antibodies to form beads-E. coli-APLAE conjugates by antibodyantigen reaction. The conjugates were separated by a magnetic field and then incubated with phenyl phosphate to produce phenol. An amperometric tyrosinasehorseradish peroxidase biosensor in a flow injection system was used to detect the phenol concentration that is proportional to the cell number of E. coli O157:H7. The biosensor was evaluated using samples of chicken carcass wash water, ground beef and fresh-cut broccoli. This biosensor was able to detect as few as 6 10 1 cells/ml of E. coli O157:H7 under optimized conditions (1 mM MgCl2, 0.4 mg/ml APLAE, and 1 mM phenylphosphate in 25 mM Tris buffer solution pH 10.0). The total detection time from separating target bacteria with immunomagnetic beads to analyzing flow injection electrochemical detection was approximately 2 h.

(Download PDF)    (Export to EndNotes)