Autochthonous lactic acid bacteria as candidate protective cultures for microbial control in raw milk cheeses: A critical scoping review of mechanistic evidence and bioprotective potential

Autochthonous lactic acid bacteria (LAB) from raw milk cheese ecosystems are frequently proposed as candidate protective cultures, but evidence supporting their antimicrobial mechanisms and cheese-matrix performance remains fragmented. This critical scoping review mapped antimicrobial activity, bioprotective potential, assessment methods and mechanistic evidence for autochthonous LAB associated with raw milk cheese ecosystems. Searches in Scopus, Web of Science, and PubMed followed PRISMA-ScR. Thirty-seven studies met eligibility criteria. Antimicrobial assays were standardized by assay format, tested material, assay-specific modifications, and mechanistic validation, and a decision framework distinguished screening from mechanism-supported evidence. Listeria monocytogenes was the most frequent target. Diffusion-based assays and cell-free supernatants predominated, whereas cheese-system validation was uncommon. Most studies (24/37) lacked sufficient differentiation for reliable mechanism assignment, and bacteriocin-mediated activity was confirmed in only two studies. Overall, antimicrobial activity was common but strain-dependent, with limited evidence linking inhibition to defined mechanisms and cheese performance.