Bile Esculin Agar Slant in Tubes

This slant is recommended for differential isolation and presumptive identification of group D Streptococci in food and pharmaceutical products. Enterococci and Group D Streptococci exhibit esculin hydrolysis. Esculin is hydrolysed to esculetin and dextrose, which reacts with ferric citrate producing brownish black precipitate. Leuconostoc, Pediococcus, Lactococcus species causing human infections give a positive bile esculin test. It can be supplemented with 50ml/L horse serum. Selective due to presence of bile.