SURFACE PLASMON RESONANCE BASED IMMUNOSENSING OF E. COLI O157:H7 IN APPLE JUICE

Abstract

Escherichia coli O157:H7 was detected in apple juice using an alkanethiol self-assembled monolayer (SAM)based surface plasmon resonance (SPR) immunosensor. Antibodies against E. coli O157:H7 were immobilized on the sensorchip, and apple juice (100%), with no added sugar, was spiked with 105, 106, 107, and 108 CFU/mL of E. coli O157:H7 andinjected over the immobilized antibodies, followed by a pulse of antibodies to complete a sandwich assay. The detection limitand specificity of detection were assessed, and the deterioration of the antibody surface with time was also investigated. Aslow as 106 CFU/mL of E. coli O157:H7 could be detected using the sandwich assay in less than 1 h. The technique couldspecifically detect E. coli O157:H7 in apple juice in the presence of Staphylococcus aureus. This study shows that an SPRimmunosensor has the potential for applications in rapid and label-free detection of pathogens such as E. coli O157:H7 infood.