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

Fermented milk is a well-established vehicle for delivering probiotic 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 Lactobacillus gasseri BC9, BC12) for inclusion in a functional fermented milk made with skimmed milk and the exopolysaccharide-producing starter 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 largest 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 acids, notably in BC5 after fermentation and BC4 during storage. Each strain influenced volatile compound profiles differently, with increases in acetic acid and various fatty acids observed. Antimicrobial assays demonstrated strong and sustained activity from BC1 and BC5 against E. coli (ETEC), Yersinia enterocolitica, and Salmonella Typhimurium 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 probiotic viability, technological traits, and sensory attributes in formulation.