Mechanism-Guided Food Preservatives: Molecular Targets, Biofilm Control, and Food Matrix Validation

Food-compatible preservatives can control foodborne pathogens, but their performance depends on the organism, treatment conditions, food matrix, and regulatory status of the intended use. This review examines nisin, essential oil phenolics, organic acids, chitosan, and selected polyphenols, with emphasis on molecular mechanisms, biofilm control, antimicrobial combinations, nanoencapsulation, and validation in foods and on food-contact surfaces. The evidence shows that intrinsic antimicrobial activity alone cannot predict practical efficacy. Biofilm outcomes depend strongly on the endpoint measured, while interaction claims require quantitative testing rather than inference from presumed target complementarity. Nanoencapsulation can improve stability, dispersibility, release behavior, or delivery in food systems, but it does not consistently increase antimicrobial potency, and carrier effects must be distinguished from delivery effects. Food composition, surface material, biofilm age, contact time, sensory acceptability, and regulatory use conditions can substantially alter performance. Practical preservative selection therefore requires matching the antimicrobial and formulation to the target organism, application setting, measured endpoint, and conditions of use, followed by validation in the intended food or processing environment.