Zinc Oxide and Graphitic Carbon Nitride/ ZnO Nanocomposites in Food Safety and Preservation: Synthesis, Antimicrobial Mechanisms, and Application Prospects

ABSTRACT Foodborne disease remains a major global health and economic burden, with recent World Health Organization estimates attributing roughly 866 million illnesses and 1.52 million deaths annually to 42 major foodborne hazards. Conventional preservation and decontamination strategies are increasingly challenged by antimicrobial‐resistant pathogens, chemical residues, and mycotoxin contamination, creating demand for complementary nanotechnology‐based interventions. Zinc oxide (ZnO) nanoparticles and their heterojunctions with graphitic carbon nitride (g‐C 3 N 4 ) have emerged as versatile platforms combining broad‐spectrum antimicrobial activity with visible‐light‐driven photocatalytic detoxification. This review synthesizes recent literature on the synthesis of ZnO nanoparticles by conventional and green/biogenic routes, including microbially mediated synthesis using actinobacteria such as Streptomyces species, and on the design of g‐C 3 N 4 /ZnO S‐scheme heterojunctions that suppress charge‐carrier recombination while preserving strong redox potentials. We examine the principal antimicrobial and photocatalytic mechanisms—reactive oxygen species generation, Zn 2+ ion release, and direct membrane interaction—and their translation into food‐relevant applications, including antimicrobial active packaging films and coatings, photocatalytic degradation of mycotoxins and pesticide residues, and nanomaterial‐based biosensors for pathogen and spoilage detection. Toxicological and regulatory considerations, including nanoparticle migration from food‐contact materials and evolving European Food Safety Authority and United States Food and Drug Administration frameworks, are discussed alongside persistent gaps in standardized safety testing, scale‐up reproducibility, and life‐cycle assessment. We conclude by outlining research priorities—particularly the systematic evaluation of biogenic ZnO and g‐C 3 N 4 /ZnO composites under real food matrices and regulatory‐relevant conditions—needed to advance these materials from laboratory demonstration toward safe, standardized, and sustainable adoption across the food value chain.