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

The interaction between probiotic (<i>Enterococcus spp., Lactobacillus </i><i>spp., and Lactococcus spp</i>.) and enteric (<i>Bacteroides spp., Escherichia coli, </i>and <i>Salmonella spp</i>.) 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<i> E. coli </i>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.<br />