Mixed cultures of food-grade probiotic bacteria and enteric bacteria demonstrate both synergism and inhibition on menaquinone production

The interaction between probiotic (Enterococcus spp., Lactobacillus spp., and Lactococcus spp.) and enteric (Bacteroides spp., Escherichia coli, and Salmonella spp.) bacteria with respect to menaquinone production was examined. Menaquinones were measured in cell pellets by high-pressure liquid chromatography and the main homologues produced were MIK_7–11. The growth of both Bacteroides and E. coli cultured with the 3 probiotics was significantly inhibited with concomitant reduction in menaquinone production. The vitamin K status of humans could be affected by consumption of probiotic dairy foods via the contribution made by gut microflora.