On-Site Generation of Coreactant on a Solid-State Electrochemiluminescence Electrode for Label-Free Detection of Enterohemorrhagic Escherichia coli in Raw Meat Samples

Rapid and accurate detection of trace microbial pathogens is essential for human health, environmental monitoring, and food safety. Here, we report the development of a solid-state electrochemiluminescence (ECL) bacterial sensor based on a β-glycosidase (β-Gal)-triggered coreactant generation strategy. Leveraging a three-dimensional TiO2 nanotube array integrated with peroxidase-like MIL-53(Fe), glucose oxidase-like Au nanoparticles, and luminol, this sensor efficiently generates coreactants on-site, enabling sensitive glucose detection. As glucose is the primary product of β-Gal-catalyzed lactose hydrolysis, its concentration directly correlates with β-Gal enzymatic activity, thus allowing for the quantification of β-Gal via ECL signal intensity. Using enterohemorrhagic Escherichia coli (EHEC) as a model of food-borne pathogens, the sensor demonstrates rapid detection (30 min) with an ultralow LOD (0.8 CFU mL–1), representing the most sensitive label-free bacterial ECL sensor reported to date. Furthermore, the ECL electrode was applied for the detection of EHEC on raw salmon slices, underscoring its potential for food safety monitoring.