Isolation and Identification of Bifidobacterium spp.in Commercial Yogurts Sold in Europe

Abstract

A new selective medium, galactose (GL) agar, was developed for the enumeration of Bifidobacterium spp. in yogurts . This medium contains lithium chloride (0.4 g/1) and galactose (10 g/l) as selective inhibitory agents. The viable counts of bifidobacteria in the commercial yogurts sold in Europe were determined by using GL agar. From five of eight commercial yogurts tested , bifidobacteria were detected in 104-107 per ml, while from the remaining three they were not detected. Five Bifidobacterium strains isolated were identified on carbohydrate fermentation patterns and DNA-DNA homology. Only one strain was classified B. longum and the remaining four strains as B. animalis.