Probiotics in the new millennium.

Beneficial effects on human health by specific probiotic microorganisms such as prevention of gastrointestinal tract infections immune stimulation, and balancing of the intestinal microflora have been established in numerous clinical trials. The successful probiotic strains which are mainly members of Lactobacillus and more recently Bifidobacterium naturally found in the human intestinal tract, have been traditionally incorporated into fermented milk products but have excellent potential for further inclusion in functional foods and health-related products. While the health claims are generally accepted by both scientists and consumers, often the molecular mechanisms underlying the probiotic properties remains controversial. Further progress concerning the molecular basis of probiotic traits will give vital reinforcement to the probiotic concept and is a prerequisite for rational development into further applications. In this review, current research on the genetics of properties of the intestinal lactobacilli that may contribute to the activity and effectiveness of probiotics is described. The potential of molecular biology for future probiotic applications is addressed and a probiotic strains developed by modern biotechnology with advantages for specific consumers is presented.