A novel, simple and low-cost paper-based analytical device for colorimetric detection of Cronobacter spp.

摘要

Cronobacterspp. are recognized as a world-wide emerging opportunistic food-borne pathogens that can persist in various food and processing environment for a long time. Therefore, the prevention and detection of them are particularly important. In this study, a micro-spot paper-based analytical device (μPADs) was created by combining PVC pad with filter paper. Detection is achieved by measuring the color change (from colorless to indigo) when a species-specific enzyme associated with theCronobacterspp. of interest reacts with a chromogenic substrate. When combined with the optimization of specific enrichment process, the method allows for a testing time of 10?h or less and is capable of detecting live bacteria on the inoculated surface of samples in concentrations as low as 101?CFU?cm?2. We are surprised to discover thatC.?dublinensisspecies and their subspecies had the highest ability to produce α-glucosidase in all genus ofCronobacterspp.. This work demonstrated that the manufacturing method is novel, simple, well reproducible (RSD less than 5%) and low-cost (less than $ 0.15 per micro-spot).