PDMS microfluidic chips were fabricated using a 3D molding method and a multiplex CAMP assay was proposed on the chip for the visual detection of C. sakazakii in powdered infant formula.

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Summary Shigella is the main cause of endemic diarrhoea in low‐income countries. Fast and accurate detection of this pathogen can effectively prevent the consumption of contaminated food and reduce the risk of diarrhoea outbreaks. Recently, a competitive annealing‐mediated isothermal amplification (CAMP) assay was proposed as a novel nucleic acid detection technology. In this study, we developed a visual CAMP assay based on the invasive plasmid antigen H (ipaH) gene for rapid detection of Shigella in milk. Without enrichment culture, the visual CAMP assay could reliably detect Shigella at 2.6 × 102 CFU mL−1 or higher contamination levels. With enrichment culture, even if the spiked level is 1 CFU mL−1, the visual CAMP assay could reliably detect Shigella from the milk sample. Furthermore, a simple paper‐based DNA extraction method was established. The efficiency of the paper‐based method was comparable to that of the commercial kit method, and the entire extraction procedure can be completed in 15 min. The visual CAMP assay combined with the paper‐based DNA extraction method showed higher sensitivity and specificity for Shigella on‐site detection in milk samples.