Recombinase Polymerase Amplification Combined with Unmodified Gold Nanoparticles for Salmonella Detection in Milk

Salmonella is one of the most common pathogenic bacterium, which causes food spoilage and human diseases. The national standard detection method (GB4789.4) and other fast detection methods for Salmonella cannot satisfy the requirements in the present climate because of their inefficiency, low accuracy, high equipment requirements, or high cost. In this study, we combine isothermal recombinase polymerase amplification (RPA) with unmodified gold nanoparticles (AuNPs) to detect Salmonella in milk. A rapid, effective, visualized, and low-cost RPA-AuNP assay was developed, with a detection limit of 50CFU for milk samples after enrichment for 6h or 1pg for DNA within 15min at 37 degrees C using simple water bath equipment. Furthermore, it exhibited no cross-reactions with other pathogens by using highly specific region of invA of Salmonella as the target detection gene. And it may apply to the local food inspection and detection center whose equipment conditions are poor.