Innovative Fermented Milk Product Enriched with Vaginal Probiotics for Women’s Health

Aim: Fermented milk is widely acknowledged as an effective vehicle for delivering probiotics and is increasingly considered a functional food. This research, conducted within the framework of the FUNPRO-L project, aimed to identify the most suitable probiotic among five vaginal isolates (Lactobacillus crispatus BC1, BC4, BC5, and Lactobacillus gasseri BC9, BC12) for inclusion in a functional fermented milk product formulated with the EPS-producing starter culture ST-440 (Streptococcus thermophilus, Sacco). Method: In a first screening, the survival of the probiotic strains was evaluated after fermentation and after 28 days of storage at 5°C. BC1, BC4 and BC5 were selected for further trials at a concentration of 8 log CFU/ml. The technological properties, including water holding capacity and rheological properties, were evaluated. In addition, the release of free amino acids and the profiles of volatile compounds as well as the antimicrobial activity against E. coli (ETEC), Yersinia enterocolitica and Salmonella typhimurium were analysed. Based on the laboratory results, one strain was selected for further testing in an industrial-scale trial. For this trial, 50 litres of lactose-free skimmed milk were used, whereby different fermentation conditions and different times of addition of the vaginal co-starter to the matrix were investigated. Results: Among the three vaginal strains preliminary selected (BC1, BC4, BC5), BC1 showed the best viability (0.5 log reduction), followed by BC5, while BC4 showed the greatest reduction in viable cells. BC5 showed superior technological properties, including the highest water holding capacity (23.3%) and better rheological properties. The addition of probiotics improved the release of free amino acids, especially in BC5 after fermentation and in BC4 during storage. The profiles of volatile compounds changed according to the individual strains, with increased levels of acetic acid and fatty acids. Antimicrobial tests showed that BC1 and BC5 had strong activity against the selected pathogens. Conclusion: BC1 and BC5 were identified as strong candidates for use in probiotic dairy products targeting women’s health. In particular BC5 was finally selected for industrial validation due to its balanced profile of microbial stability, functional performance and functional properties.