A discovery of Enterobacter sakazakii in formula milk which is caused meningitist, enterocolitist, and septic in several years ago decreased Indonesian people milk consumption especially who took formula milk for additional breast milk early. The weakness of pathogenic bacteria treatment with antibacterias which was often made ressistance need toughfully for another alternative therapy. Additional 2%, 4%, and 6% kefir grain into whole of milk can increase milk pH as a result of increase lactic acid bacterias (BAL) which produces antibacterias compound as organic acid, bacteriocin, and hydrogen peroxide. Whole of milk samples which is used as much as fourteen samples from different cow and the
type of cow must be Friesian Holstein taken from morning milking. Obtainable data is taken by inhibiting zone measurement with cakram disc and five times
proceeding. It is treated by using statistic test named Kruskall Wallis with significant result p<0,05 and Mann Whitney test for finding out the differences in
every concentration groups. The result has no meaningful difference in every groups. However, it has meaningful difference both positive control and negative
control group. The cow’s age affect inhibiting zone. Proper cow kefir milk is obtained as well as cow’s getting older.