Abstract
A culture method was developed suitable for selective cell counting of bifidobacteria in Japanese commercial dairy and pharmaceutical bacteria products.
1) A dissolved agar medium was added at 45°C to the bacterial suspension in the bottom of a test tube to achieve a deep culture medium, then the culture was incubated. The present culture method in the agar column, tentatively called the test tube method by the authors, was suitable for carrying out anaerobic incubation for viable cell counting of bifidobacteria.
2) Modified Garche's agar with lithium chloride (MGL agar) or with lithium chloride and penicillin G potassium (MGLP agar) was demonstrated to be a suitable medium for the selective cell counting of bifidobacteria by the test tube method described, above since it discriminated the growth of lactobacilli and streptococci.
3) Bifidobacteria in commercial dairy and pharmaceutical bacteria products were determined satisfactorily by the present test tube method with MGL agar or with MGLP agar, except for products which contained enterococci.
