In a double-blind , randomised , placebo-controlled pilot study with children aged @-@ years , @ received @ @ ( @ ) colony-forming units of Lactobacillus acidophilus CUL@ ( NCIMB @ ) , Lactobacillus acidophilus CUL@ ( NCIMB @ ) , Bifidobacterium bifidum CUL@ ( NCIMB @ ) and Bifidobacterium animalis subsp .