KCS

Sensing strategies for foodborne pathogens have been developing as rapidly analyzing, convenient and cost-effective sensors throughout the past decades. Here, we developed a three-dimensional paper sensor for five species of foodborne bacteria, Escherichia coli, Escherichia coli O:157, Salmonella spp., Staphylococcus and Listeria monocytogenes, with using the chromogenic substrates specific to the enzyme of each bacterium. This compact-sized sensor was fabricated with multi-layered filter paper which is patterned by wax-ink to form hydrophobized walls in the paper matrix. Each layer contains lysis, oxidizing and chromogenic substrate reagent for effective enzyme-substrate reaction. Each pathogen was qualitatively detected by observing the color developments of the bottom layer with naked eyes. Further quantitative analysis was realized by digitalizing the color changes. The color developments were detectable within 30 min after injecting 50μL of sample. When conducted with enrichment step (taking 12 hours or less), the sensor was able to sensitively detect as low concentration of the analytes as 10¹ cfu/ml. The three-dimensional paper sensor is potable, selective and easy-to-use analytic device for first screening detection and quantitative analysis of foodborne pathogen.