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Human milk provides beneficial bacteria, including lactic acid bacteria (LAB), which shape the infant gut microbiota, enhance barrier function and immune responses, and protect against pathogens. This study evaluated the probiotic potential of three human milk-derived LAB strains: Lacticaseibacillus rhamnosus B5H2, L. rhamnosus B9H2, and L. paracasei B10L2. Initial screening revealed L. rhamnosus B5H2 higher antimicrobial activity against key foodborne pathogens (halos >1 cm), adhesion to Caco-2 cells (18.77%), and significant inhibition of Salmonella enterica adhesion (22.1%). Notably, this study evaluated these strains within diverse fermented food matrices (cow milk, whey, and soy drink) providing insight into matrix-dependent modulation of probiotic functionality. Probiotic-soy-based matrices exhibited broad antimicrobial effects (B5H2 consistently outperformed other strains). The strains showed high survival during in vitro gastrointestinal digestion, especially in cow milk and whey, highlighting strain-matrix synergy as a factor for probiotic efficacy. B5H2 strain was selected for encapsulation (spray-dried with maltodextrin and encapsulated in a gastric-resistant capsule) and further characterization. Simulated gastrointestinal digestion of the encapsulated strain in all matrices preserved high viability post-colonic phase (above 8 Log CFU/mL). Then, intestinal digests were applied to Caco-2 cells, where whey-B5H2 significantly enhanced cell viability (193.4 ± 8.8% vs. 105.5 ± 14.0% in control). Furthermore, B5H2 digests, particularly derived from cow milk, significantly reinforced intestinal barrier integrity under normal and inflammatory conditions. By integrating encapsulation technology, real food matrices, and post-digestion functional assays, this work provides a novel physiologically relevant framework for probiotic evaluation. L. rhamnosus B5H2 is a promising candidate for functional food applications targeting gut health. • Fermented soy, milk, and whey beverages with three Lacticaseibacillus strains exhibited antimicrobial activity. • The strain L. rhamnosus B5H2 showed strong antimicrobial activity, adhesion capacity and reduced the adhesion of Salmonella spp . efficiently. • Encapsulated L. rhamnosus B5H2 in real food matrices maintained high viability after in vitro simulated digestion. • Intestinal digestion products, derived from Lactobacillus rhamnosus B5H2 in food matrices, increased Caco-2 cell viability and strengthened intestinal barrier function.
Moreno et al. (Wed,) studied this question.