Rechargeable N-Halamine Hydrogel Paint Coating Based on Upcycled Sesame Meal Protein for Preventing Cross-Contamination on Food-Contact Surfaces.

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.