In a double-blind , randomised , placebo-controlled pilot study with children aged 3-6 years , 57 received 1.25 10 ( 10 ) colony-forming units of Lactobacillus acidophilus CUL21 ( NCIMB 30156 ) , Lactobacillus acidophilus CUL60 ( NCIMB 30157 ) , Bifidobacterium bifidum CUL20 ( NCIMB 30153 ) and Bifidobacterium animalis subsp .