A method for producing bacteria belonging to the genus Bifidobacterium having excellent viability even under various conditions with different environmental factors, novel bacteria belonging to the genus Bifidobacterium obtained by the method, and a method for detecting the bacteria are provided. By subculturing and storing bacteria belonging to the genus Bifidobacterium alternately in systems under conditions with different environmental factors, the bacteria belonging to the genus Bifidobacterium exhibiting excellent viability under all the conditions used for the alternate subculturing and storing can be produced.
