Characterisation of SapYZUs891@Fe/Mn-MOF Provides Insight into the Selection of Temperate Phage and Nanozyme for the Rapid and Sensitive Colourimetric Detection of Viable

Although phage@nanozymes have proven to be a rapid, precise, and cost-effective method for detecting pathogens in food, the basis of phage and nanozyme selection remains poorly understood. In this study, a novel colourimetric biosensor utilising the temperate phage SapYZUs891 and an Fe/Mn-MOF nanozyme was constructed and assessed for its efficacy in detecting Staphylococcus aureus in food products. Notably, SapYZUs891 exhibited a high titre, broad host range, and strong pH and thermal stability. Moreover, the bimetallic Fe/Mn-MOF nanozyme exhibited an enhanced oxidase-mimicking ability, greater affinity, and a higher reaction rate. The biosensor had a detection time of 19 min, a detection limit of 69 CFU/mL, and a recovery rate between 92.52% and 121.48%, signifying its high reliability and accuracy in identifying S. aureus. This sensor distinguishes between viable and non-viable bacteria and demonstrates resistance to interferent bacterial and food compounds, likely attributable to the particular receptor-binding proteins of SapYZUs891 that bind to the teichoic acid wall on the S. aureus. These results indicated that the SapYZUs891@Fe/Mn-MOF is suitable for the rapid visual assessment of S. aureus. Moreover, the highly sensitive and specific detection system holds significant potential for extended application in on-site screening of S. aureus contamination within food processing environments.