MILK FERMENTED WITH YOGURT CULTURES AND LACTOBACILLUS-CASEI COMPARED WITH YOGURT AND GELLED MILK - INFLUENCE ON INTESTINAL MICROFLORA IN HEALTHY INFANTS

Ingestion of fermented dairy products induces changes in the equilibri um and metabolism of the intestinal microflora and may thus exert a he althful influence on the host. We compared the effects of consumption of a traditional yogurt, a milk fermented with yogurt cultures and Lac tobacillus casei (YC), and a nonfermented gelled milk on the fecal mic roflora of healthy infants. Thirty-nine infants aged 10-18 mo were ran domly assigned to one of three groups in which they received 125 g/d o f one of the three products for 1 mo. The following indexes were not m odified during the supplementation period or for 1 wk after the end of supplementation: total number of anaerobes, bifidobacteria, bacteroid es, and enterobacteria; pH; water content; concentrations of acetate, butyrate, propionate, and lactate; and bacterial enzyme activity of be ta-galactosidase and alpha-glucosidase. In contrast, in the yogurt gro up the number of enterococci in fecal samples increased (P < 0.05), wh ereas the percentage of branched-chain and long-chain fatty acids, whi ch are markers of proteolytic fermentation, decreased (P < 0.05). In t he YC group, the percentage of children with > 6 log(10) colony-formin g units lactobacilli/g feces inc;eased (P < 0.05), whereas the potenti ally harmful enzyme activity of beta-glucuronidase and beta-glucosidas e decreased (P < 0.05). These decreases were particularly marked in th ose infants in the YC group in whom activity of the enzymes was initia lly unusually high.