Rechargeable N-Halamine Hydrogel Paint Coating Based on Upcycled Sesame Meal Protein for Preventing...

Sesame meal protein isolate (SPI) derived from sesame meal was utilized as an upcycled plant protein source to develop N-halamine structure-based antimicrobial coating system to prevent cross-contamination for fresh food produce. The coating matrix was formulated using SPI, tannic acid (TA), cellulose nanocrystal (CNC), and sodium hypochlorite (NaOCl). The N-halamine structure maintained a stable active chlorine content of approximately 5 µmol/cm² and enabled repeated recharging to the initial level on the coated model food-contact surface, stainless steel (SS). The stability of the coated surface was evaluated under various harsh conditions, including different pH levels (2, 4, 7, and 9), temperatures (4°C, 23°C, and 35°C), chemical oxygen demand (COD) levels (0-20,000 mg/L), and physical damage. Antimicrobial test against Escherichia coli O6 and Listeria innocua showed a 5 log CFU/mL reduction within 5 min under at 22 ± 2°C and 45 ± 5% relative humidity. Furthermore, the SPI-based coating inhibited the transfer of bacteria to leafy fresh food produce about 4 log CFU/mL reduction in simulated cross-contamination tests. These findings suggest that the developed coating system in this study offers a stable and effective solution for cross-contamination of fresh food produce, addressing limitations of conventional biopolymer-based coatings.