| Abstract: | A method which permitted counting viable cells of Bifidobacterium bifidum N4 in a solid medium was developed. A piece of the solid medium (0.7 ml) was quantitatively obtained with the aid of an agar-puncher device and was homogenized in a Potter–Elvehjem homogenizer after the addition of 9.3 ml of sterile physiological saline. A 10-fold dilution of the homogenate was repeated several times to make a series of dilutions. An aliquot (0.2 ml) of the appropriate dilution was used for counting the viable cells using a capillary tube method. The accuracy and the reproducibility of the method were comparable with those of the conventional plate counting method. By using established procedures the behaviors of B. bifidum N4 in a solid medium were studied. Viability of the organism in a solid medium lacking an energy source (lactose) was generally correlated to the period of preculture; the longer the period of preculture, the shorter was the span of cell life. |
