The lactic acid production by L. johnsonii CRL1647,IG9,AJ5,A15and E. faecium SM21 was determined by HPLC. Interestingly, even though the pH values of the lactobacilli cultures were similar with an average value of 3.8±0.5; the lactic acid concentration profile was characteristic of each strain. L. johnsonii AJ5 synthesized the largest amount of this metabolite followed by IG9,CRL1647 and A15 Table2). While, E. faecium SM21,also a homofermentative lactic acid bacteria, acidified BHI broth at pH 4.5 and produced the lowest concentration of lactic acid. BHI broth was selected to culture Enterococcus spp. Because it was determined in the laboratory that MRS broth was not as efficient for cocci growth.