RESEARCH NOTE - UNSUITABILITY OF THE MRS MEDIUM FOR THE SCREENING OF HYDROGEN PEROXIDE-PRODUCING LACTIC-ACID BACTERIA

The effect of MRS broth on the stability of hydrogen peroxide (H2O2) h as been studied. Known concentrations (1-100 mu g ml(-1)) of H2O2 were prepared in distilled water, phosphate buffer (pH 7.0) and MRS broth (pH 6.2 and 3.9). H2O2 was very stable in aqueous and buffer solutions but it was rapidly degraded in MRS broth (pH 3.9). The presence of H2 O2 in MRS broth (pH 6.2) could not be detected.