Characterization and Antimicrobial Activity Assessment of Postbiotic-Loaded Chia Mucilage–Montmorillonite Films Developed for Food Systems

This study presents the development and characterization of chia mucilage-montmorillonite (MMT) films enriched with <i>Lactobacillus sakei</i> postbiotics. The films were evaluated mainly for their antimicrobial properties and practical applicability in food systems. The postbiotic contained 21 phenolic compounds and 60 volatile metabolites that exhibited inhibitory activity against <i>Escherichia coli</i> O157:H7 and <i>Listeria monocytogenes</i>. Incorporation of postbiotics and MMT into chia mucilage significantly enhanced antimicrobial performance. Rainbow trout (<i>Oncorhynchus mykiss</i>) fillets were used as a model food system to demonstrate practical applicability, and their shelf life was extended by 9-15 days compared with controls. These findings confirm the potential of postbiotic-loaded chia mucilage-MMT films as promising bioactive packaging materials for food systems, combining natural antimicrobial activity with improved preservation capacity.