Streptococcus mutans Growth Inhibition by the Probiotic Lacticaseibacillus rhamnosusGG as an Additive to Infant Formula

Probiotics have demonstrated Streptococcus mutans (SM) suppression. This in vitro study compared the SM inhibition capacity of bovine infant formula supplemented with Lacticaseibacillus rhamnosus Gorbach Goldin (LGG) probiotic to a plain formulation. Methods Two bovine‐based infant formulas, Similac Advance Optigro (formula non‐probiotic, FNP) and Enfamil Nutramigen LGG (formula with probiotic, FWP) were compared. The formulas were reconstituted at different concentrations (0.1×, 0.5×, 1×, and 2×). LGG (ATCC BAA‐3227) suspensions were used as positive controls. All assays were inoculated with SM, spiral plated ( n = 8) onto selective Mitis Salivarius Agar plates, and incubated at 37°C for 96 h. SM growth was enumerated in colony‐forming units (CFU). Multivariate analysis of variance was performed to assess concentration‐dependent effects and statistical significance ( α = 0.05). Results FWP recorded less SM growth than FNP at the 0.5×, 1.0×, and 2.0× concentrations (ANOVA p < 0.001). FWP concentration was negatively correlated to SM growth ( p < 0.001, r = −0.864), whereas FNP showed strong positive trends ( p < 0.001, r = 0.821). MANOVA tests confirmed that both group and concentration affect SM growth ( p < 0.001). Conclusion Commercial probiotic‐enriched infant formula effectively suppresses SM growth in vitro. The observed suppression of SM growth in this study provides evidence for this dietary intervention's anticariogenic potential.