Abstract
The effects of Bifidobacteria-fermented milk on human urinary mutagenicity, which increases following ingestion of cooked ground beef, and fecal microflora were investigated using ten healthy volunteers. The urinary mutagenicity was determined by means of Ames Salmonella test. The mutagenicity of urine samples after the ingestion of cooked ground beef during the drinking of Bifidobacteria-fermented milk was significantly lower than that of urine samples before and after drinking (p<0.05). Whereas for unfermented milk, a significant difference was found between during and after drinking (p<0.05). Regarding the changes in fecal microflora, administered Bifidobacterium breve strain Yakult and B. bifidum strain Yakult were recovered in the respective quantities 7.65±0.41 and 8.41±0.36 (log10CFU, means±SD/g-feces) during the drinking of Bifidobacteria-fermented milk. A significant increase in Lactobacillus was observed in the subjects during the drinking of Bifidobacteria-fermented milk compared with before and after drinking (p<0.001 and p<0.002, respectively). In addition, a significant decrease in the number of Enterobacteriaceae was observed during drinking for both Bifidobacteria-fermented and unfermented milk (p<0.01). These results suggest that the drinking of Bifidobacteria-fermented milk may be effective in reducing the carcinogenic risk associated with ingestion of cooked ground beef in meal.
