Evaluation of different selective media for enumeration of probiotic micro-organisms in combination with yogurt starter cultures in fermented milk

摘要

The aim of this study is to assess selective plating methodologies for the enumeration and identification of?Streptococcus thermophilus,?Lactobacillus delbrueckii?ssp.?bulgaricus, Lactobacillus acidophilus,?Lactobacillus rhamnosus?and?Bifidobacterium animalis?ssp.lactis?in fermented milks. Seven agar media (MRS with added sorbitol, clindamycin or vancomycin, acidified MRS, RCA with added aniline blue and dicloxacilin, M17 and ST) were evaluated. The results showed that RCA dicloxacilin agar is suitable for the selective enumeration of?B. animalis?ssp.?lactis?in fermented milk.?Either MRS (acidified) or M17 agar could be used for enumeration of?L.?delbrueckii?ssp. bulgaricus?and?S. thermophilus,respectively. MRS media containing antibiotics were effective for the enumeration of the probiotic organisms (L. rhamnosus?and?L. acidophilus) inoculated in fermented milks.