Growth Characteristics of Bifidobacteria in Infant Formulas

Abstract

Four species of bifidobacteria, Bifidobacterium bifidum (ATCC 15696), Bifidobacterium breve (ATCC 15700), Bifidobacterium infantis (ATCC 15697), and Bifidobacterium longum (ATCC 15708), were grown anaerobically at 37°C in lactobacilli MRS broth with 0.5% cysteine-HCl and inoculated at 2.5% into three types of infant formula (based on soy, or milk, or casein hydrolysate) and in nonfat milk followed by incubation at 37°C for 24 h. In most cases, the logarithmic phase of growth for all species varied from the first 8 to 12 h postinoculation. Generation times for B. longum and B. breve were similar, and times for B. infantis were shortest, in all of the formulas. Trends for lactic acid production for all species in all the formulas were similar to trends for acetic acid production. Counts for formulas based on soy or milk were similar for all species except B. bifidum, and those for casein-hydrolyzed formula were always lowest for all species except B. bifidum, for which count was maximal with the formula based on soy. Results suggest that growth characteristics of bifidobacteria in infant formula were species specific and formula dependent and that growth was maximal in the formula based on milk.