The effects of yoghurt on fecal flora and fecal putrefactive products were studied in eight healthy male volunteers (aged, 38-59 years) who consumed 500 g of yoghurt once a day for 2 weeks. The yoghurt was prepared with Lactobacillus delbrueckii subsp. bulgaricus strain 2038 and Streptococcus salivarius subsp. thermophilus strain 1131. On day 14 of yoghurt consumption, Clostridium and Lactobacillus tended to decrease in number, while bifidobacteria significantly increase (p<0.05) in 5/8 volunteers who used to have a small number of bifidobacteria in the intestines. No detectable changes occurred in the level or the incidence of other organisms. The fecal pH values did not change remarkably during yoghurt consumption. Such putrefactive products as ammonia and indole in the stools decreased significantly (p<0.05) during yoghurt consumption. No significant changes were shown in the hemogram throughout the experimental period.
