Rapid and interference-resistant colorimetric detection of viable Staphylococcus aureus in food using a broad host range phage SapYZU04 and MnFeO nanozyme

Bacteriophage-based biosensors have the potential for rapid, convenient, and sensitive detection of Staphylococcus aureus in food products; however, their effectiveness is often limited by the host range of the bacteriophage. This study presents a new colorimetric biosensor using the S. aureus phage SapYZU04 exhibiting a broad host range, and a MnFeO nanozyme for the effective detection of S. aureus in food products. Notably, SapYZU04 exhibited excellent features, such as a high titre (1.0 × 10 10  PFU/mL), a short latency period (5 min), a large burst size (210 PFU/cell), a wide host spectrum (98.95%, 94/95), and good stability at pH 3.0–12.0. The biosensor, referred to as SapYZU04@MnFeO was constructed by immobilising SapYZU04 on the MnFeO nanozyme via electrostatic interactions. SapYZU04@MnFeO demonstrated a broad detection range of bacterial concentrations, particularly within the range of 3 × 10 2 to 3 × 10 9  CFU/mL, with a low detection limit of 65 CFU/mL and rapid detection time (14 min). Furthermore, it exhibited high accuracy in detecting and quantifying live S. aureus with recovery rates ranging from 92.21% to 105.56%. The chromogenic system demonstrated high selectivity for S. aureus and was unaffected by other interfering microorganisms or food preservatives, highlighting its specificity and interference-resistance. Whole-genome sequencing of SapYZU04 suggested that the selectivity, sensitivity, and specificity of SapYZU04@MnFeO could be attributed to the tail fibre proteins of the phage. In conclusion, the SapYZU04@MnFeO biosensor is a highly effective tool for identifying viable S. aureus strains in the food industry.