Selective medium for isolation and enumeration of Bifidobacterium spp.

A new method was developed for the isolation and enumeration of Bifidobacterium spp. from natural aquatic environments. The method was based on the utilization of a new medium, Bifidobacterium iodoacetate medium 25, and resuscitation techniques were used to isolate injured bifidobacteria. The new medium was tested with a nonselective reference medium on sewage and sewage-polluted surface waters. Relatively little colonial growth of any other bacterial genera occurred; when such colonies did grow, Bifidobacterium could be easily differentiated by its colonial morphology or, after Gram staining, by its typical bifidobacterial morphology.