Influence of breast-feeding on the bifid flora of the newborn intestine.

Because of the predominance of Bifidobacterium bifidum in the intestine of the breast-fed infant, growth promoting factors were sought in human milk. In vitro, studies showed the presence of specific growth factors for B. bifidum in human milk. Other milks, including cow's milk, sheep's milk, pig's milk, and infant formulas did not promote the growth of this species, but did show activity on Bifidobacterium infantis and Bifidobacterium longum.