Abstract

Gastrointestinal microflora exerts a high impact on its host mainly by performing a great variety of metabolic activities, protecting the host against colonization by pathogen and stimulating the gut immune system. The integration of bifidobacteria in dairy products is of interest for reinstalling the intestinal microflora. The mother's milk is a prebiotic factor which stimulate the bifidobacteria growth in vivo. Results obtained in west Algeria area show that the number of bifidobacteria reach 26 10⁹ cfu/g in breast-fed infant feces. The microbiological, fructose–6-phospho-ketolase and the biochemical tests have revealed Bifidobacterium strains. The most prevalent isolates belong to the species Bifidobacterium longum (75%) and Bifidobacterium breve (25%). In order to evaluate the potential use as a starter culture, the occurrence of some selected properties such as growth and survival in fermented milk were investigated. These strains have a fast growth in glucose, galactose and lactose media compared to reference species. All isolates studied are sensitive to the pH 8. The B. breve strain support the conservation conditions in pure culture better than in mixed culture with Streptococcus thermophilus or Lactobacillus acidophilus.

Key words: Lactic acid bacteria, Bifidobacterium, probiotic, fermented milk, growth, survival.