Novel receptor-binding protein from phage PJNS004 for sensitive detection of Salmonella

The detection of Salmonella, a key foodborne pathogen, is essential for maintaining food safety and safeguarding public health. Here, we have identified a novel receptor-binding protein (RBP), encoded by ORF33 of phage PJNS004, that specifically targets lipopolysaccharide on the host strain surface. To utilize this RBP for Salmonella detection, we expressed and purified the recombinant protein, designated as proSM and proM. Based on the principle of ELISA double antibody sandwich method, our developed two-step method boasts a detection limit of 10 CFU/mL and a rapid binding time of 30 min. The reliability and sensitivity of our method were further confirmed in food (lettuce, chicken breast, and milk) and clinical samples, with recovery rates ranging from 98 to 105 % and 85 to 115 %, respectively. In conclusion, our study presents a novel RBP from PJNS004 and a sensitive detection method for Salmonella, offering a valuable tool for food safety and clinical diagnostics.