Designing fermented milk with targeted probiotics: a step toward female-focused functional foods

Fermented milk is a well-established vehicle for delivering pro- biotic bacteria, with growing interest in its potential as a functional food to support human health. As part of the FUNPRO-L project, this study aimed to identify the most suitable probiotic strain among five of vaginal origin (Lactobacillus crispatus BC1, BC4, BC5 and Lactoba- cillus gasseri BC9, BC12) for inclusion in a functional fermented milk made with skimmed milk and the exopolysaccharide-producing start- er culture ST-440 (Streptococcus thermophilus, Sacco). Initial screening assessed the survival of the strains in the post-fermentation and after 28 days at 5°C. BC1, BC4, and BC5 were selected for further testing at a concentration of 8 log CFU/ml. Among them, BC1 showed the best viability (0.5 log reduction) followed by BC5, while BC4 had the larg- est decrease. Technologically, BC5 outperformed others, maintaining the highest water-holding capacity (23.3%) and superior rheological properties. Probiotic addition enhanced the release of free amino ac- ids, notably in BC5 after fermentation and BC4 during storage. Each strain influenced volatile compound profiles differently, with increas- es in acetic acid and various fatty acids observed. Antimicrobial as- says demonstrated strong and sustained activity from BC1 and BC5 against E. coli (ETEC), Yersinia enterocolitica, and Salmonella Typhimu- rium throughout storage. Overall, BC1 and BC5 emerged as the most promising candidates for developing functional fermented milk aimed at improving women’s health, underlining the need to balance probiot- ic viability, technological traits, and sensory attributes in formulation.