Fe-MOF based turn-on fluorescence sensor for the rapid detection of foodborne pathogens in multiple matrices

Abstract

Ensuring food safety remains a global challenge because of the presence of foodborne pathogens, such as Escherichia coli and Staphylococcus aureus. In this study, we present a turn-on fluorescence biosensor based on an iron metal–organic framework (Fe-MOF) for the selective and rapid detection of two major foodborne pathogens, E. coli and S. aureus. Fe-MOF was synthesised via a solvothermal method and thoroughly characterised by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and thermogravimetric analysis (TGA). Upon interaction with bacterial suspensions, the sensor exhibited significant fluorescence enhancement, which was attributed to electron transfer modulation triggered by bacterial surface components. The analytical performance was evaluated across three matrices—phosphate-buffered saline (PBS), drinking water, and milk—achieving detection limits as low as 0.464 log CFU/mL for S. aureus and 0.584 log CFU/mL for E. coli. The sensor enabled rapid detection within less than 1 h with high recovery rates (95–104 %) across all tested matrices, confirming its practical usability for real sample analysis. These findings address a critical gap in biosensor research by validating Fe-MOFs for practical food-safety applications in multiple real-world environments.