Fermented food-derived antimicrobial peptides: Indonesian traditional fermented foods as an evidence base for the stability–potency paradox

Fermented food-derived antimicrobial peptides are promising natural agents for food safety and health-related applications, but their translation remains constrained by instability, matrix interference, and limited validation. This review critically examines these peptides from peptidomic discovery to functional application, using Indonesian traditional fermented foods as an underexplored regional evidence base within a broader global context. We highlight the stability–potency paradox, in which peptides with predicted or in vitro antimicrobial activity may lose function under gastrointestinal, food-matrix, or storage conditions. Key gaps include reliance on inhibition-zone assays, limited MIC/MBC standardization, incomplete strain-level identification, insufficient sequence validation, and uncertainty in distinguishing active peptides from degradation fragments. ARG-related safety concerns and the extent of risk reduction through extraction, purification, and formulation are also discussed. Comparative delivery strategies, including vesicular, lipid, polymeric, hydrogel, emulsion, and microcapsule systems, are evaluated to support more stable, safe, and application-ready peptide ingredients.