Fermented sheep milk supplemented with Lactobacillus rhamnosus NM-94: Enhancing fermented milk quality and enriching microbial community in mice

Currently, many research efforts and product developments focus on goat milk, while studies on the development and probiotic function of sheep milk remain limited. In this study, the effects of Lactobacillus rhamnosus NM-94 on the physicochemical properties, viable count, texture, microrheology, flavor, and quality detection and intestinal flora of fermented milk were analyzed by adding or not adding L. rhamnosus NM-94 to 2 starter cultures. The results showed that the addition of L. rhamnosus NM-94 to sheep milk significantly reduced fermentation time by 2 h (12 h vs. 14 h). At 21 d of storage, the count of viable bacteria in fermented sheep milk supplemented with L. rhamnosus NM-94 (0.61 ± 0.06 × 10⁹ cfu/mL) was surprisingly higher than that of the control milk (0.35 ± 0.03 × 10⁹ cfu/mL). During the microrheological analysis of the fermentation stage, the elastic index, macroscopic viscosity index, and solid-liquid balance values of fermented sheep milk supplemented with L. rhamnosus NM-94 were greater than those of the control milk, indicating that the fermented sheep milk supplemented with L. rhamnosus NM-94 had a more stable gel structure and viscosity. In mice, fermented sheep milk supplemented with L. rhamnosus NM-94 has a variety of beneficial intestinal microorganisms and potential probiotic functions. This study provides new ideas for improving the function of sheep milk and expanding the sheep milk industry.