Bifidobacterium spp. and Lactobacillus acidophilus:: biological, biochemical, technological and therapeutical properties relevant for use as probiotics

This review focuses on the biological properties and consequent technological roles of intestinal bacteria with potential health-promoting capacities, and provides selected examples available in the literature that are pertinent to the aforementioned concepts. A comprehensive overview pertaining to the taxonomy and ecology, as well as nutritional and health effects of Bifidobacterium spp. and Lactobacillus acidophilus, is provided; particular attention is paid to their incorporation, and growth and acidification features in fermented dairy products. The typical poor growth of these species in milk is highlighted, and the use of bifidogenic and growth factors, including their nature and function, is discussed. Efforts to establish optimum environmental conditions for their growth are critically reviewed, in addition to the effects of the food and storage conditions on microbial survival. Criteria for selection of effective microbial strains for their probiotic effect are listed, and modifications to improve fermentation efficiency and shelf-life of final dairy products are suggested; among these, the incorporation of Bifidobacterium spp, and L. acidophilus into a solid matrix, such as cheese, is emphasized. (C) 1999 Elsevier Science Ltd. All rights reserved.