Enhanced photostability of vitamin B2 incorporated nanofibrous membrane via covalent modification for antimicrobial photodynamic inactivation

Vitamin B 2 (VB 2 ), a natural photosensitizer, continuously generates biocidal reactive oxygen species (ROS) under light exposure, making it a promising candidate for controlling foodborne pathogen contamination. However, the photoinduced self-degradation of VB 2 limited its long-term antimicrobial application. In this work, the ribityl side chain of VB 2 was covalently linked to a poly(vinyl al co hol-co-ethylene) (EVOH) nanofibrous membrane. This covalent immobilization increased the Gibbs free energy of intramolecular hydrogen abstractions, thereby hindering the photodegradation of the VB 2 . The obtained VB 2 –EVOH exhibited continuous and stable ROS generation under both D65 and UVA irradiation across multiple light exposure cycles, with ·OH, H 2 O 2 , and 1 O 2 yields maintained at 209.89, 208.82, and 204.41 μg g −1 h −1 , respectively. The effective ROS generation resulted in approximately a 6-log reduction of Escherichia coli and Listeria monocytogenes within 60 min of photoirradiation, and this promising antimicrobial efficiency was maintained over five consecutive antimicrobial cycles without noticeable decline. Moreover, the VB 2 –EVOH demonstrated the ability to reduce various pathogenic bacteria on packaged strawberries without significantly compromising their quality, highlighting its potential application in the food-related area.