Development of endolysin-integrated pH-responsive antiadhesive and antibacterial coatings with nanorods for the prevention of cross-contamination in fresh produce.

Cross-contamination is a major food safety risk during the harvesting and processing of fresh produce, leading to significant losses in global human well-being and the economy. The surface of food contact areas is a high-risk zone for cross-contamination. Therefore, developing an effective antimicrobial coating for food-contact surfaces is essential. This study developed a smart antimicrobial coating that self-regulated in response to environmental conditions, via grafting the stimuli-responsive polymer polyacrylic acid (PAA) and the phage-derived endolysin Lysin81 onto ZnO nanocolumns. During the initial stage of bacterial adhesion, the surface of the nanocolumns exhibited significant mechanical bactericidal activity, while the super hydrophilic PAA layer effectively inhibited bacterial adhesion. At a later stage, when numerous live and dead bacteria adhered to the surface of the nanocolumns, the PAA chains disintegrated, exposing the underlying layer of endolysin that lysed the compromised bacteria. In addition, as the environmental pH increases, the attached dead bacteria can be released once the PAA chains regain their hydrophilicity. This research aimed to apply the antibacterial coating to stainless steel surfaces used in food processing, potentially enhancing surface hygiene and preventing cross-contamination of fresh produce.