A Selective Enumeration Medium for Bifidobacteria in Fermented Dairy Products

Abstract

A selective medium, blood-glucose-liver agar containing oxgall (.2 mg/ml) and gentamicin (30 micrograms/ml), was formulated for the selective enumeration of bifidobacteria in fermented dairy products containing both lactobacilli and streptococci. Recovery rates of bifidobacteria on this selective medium were around 90% of recovery on blood-glucose-liver agar. Strains of lactobacilli and streptococci were mostly inhibited with higher dilutions on this selective medium.