Publication details
Detection of Salmonella in Milk Using Enzymatic Precipitation Enhanced SPR Immunosensor
| Authors | |
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| Year of publication | 2017 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Foodborne bacterial pathogens represent a serious threat for public health. Recent outbreaks have demonstrated the need for rapid and reliable screening techniques. As an alternative to the conventional methods, various biosensors have been developed. They offer fast, sensitive, specific, robust and cost effective analysis and have a potential for point-of-care application. In this work, we have developed a surface plasmon resonance (SPR) immunosensor for the detection of Salmonella Typhimurium in powdered milk. In addition to a conventional label free SPR assay, an enzymatic enhancement step was incorporated. The method did not require any pre enrichment, making the assay fast and simple. After Salmonella was bound by capture antibody immobilized on the sensor surface, solution of detection antibody labelled by horseradish peroxidase was injected. The bound enzymatic label in turn catalyzed the precipitation of 4-chloro-1-naphthol to insoluble benzo-4-chlorocyclohexadienone. The formation of precipitate on the sensor surface provided substantial signal enhancement. The precipitation-based assay format improved the sensitivity 40 times compared to the label-free format. The limit of detection of 10^2 CFU·mL-1 in buffer and 10^3 CFU·mL–1 in milk was achieved and the whole analysis time was below 60 min. The interaction of the bacteria with the sensor surface and the formation of the precipitate were studied in detail by optical and atomic force microscopy. The developed method represents a suitable approach for routine testing of food contamination. |
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