# 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 Staphylococcus aureus in Food Products

## TL;DR

A new colorimetric biosensor using a phage and nanozyme detects Staphylococcus aureus in food quickly and accurately.

## Contribution

A novel biosensor combining a temperate phage and Fe/Mn-MOF nanozyme for rapid and sensitive detection of viable S. aureus in food.

## Key findings

- The biosensor detects S. aureus with a detection limit of 69 CFU/mL and a detection time of 19 minutes.
- The system distinguishes viable from non-viable bacteria and is resistant to interference from food compounds.
- The SapYZUs891 phage binds specifically to teichoic acid on S. aureus, enhancing detection accuracy.

## Abstract

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.