Probiotics: from research to consumer.

Intestinal microflora has metabolic, trophic and protective functions, and can be modified in pathological conditions and by the exogenous administration of probiotics. Probiotics are defined as living microorganisms which resist gastric, bile, and pancreatic secretions, attach to epithelial cells and colonize the human intestine. In the last twenty years research has been focused on the identification of the role of planktonic flora and adhesive bacteria in health and disease, and on the requisite of bacterial strains to become probiotic product which can be marketed. Probiotics can be commercialized either as nutritional supplements, pharmaceuticals or foods, but the marketing as a pharmaceutical product requires significant time, complex and costly research, and the demonstration of a well-defined therapeutic target. This review examines the sequential steps of research which, from the identification of a possible probiotic strain, lead to its production and marketing, summarizing the whole process existing behind its development, through its growth in laboratory, the studies performed to test its resistance to human secretions and stability, microencapsulation technologies, and safety tests.