A MICROBIOLOGICAL INVESTIGATION ON PROBIOTIC PHARMACEUTICAL PRODUCTS USED FOR HUMAN HEALTH

Many and different probiotic pharmaceutical products are pre sently co mmercialised in the world. On this regard, a microbiological investiga tion was carried out to screen the microorganisms incorporated into th ese products, commonly used for human health. After determination of t he cell number and viability of bacteria, several experiments were per formed in vitro in order to characterise the microorganisms and to eva luate their probiotic value. Among all the strains identified, best re sults were obtained with Lactobacillus rhamnosus, Enterococcus faecium and Saccharomyces cerevisiae as far as regards growth rates, pH and b ile salts tolerance. Moreover, the identification profiles of microorg anisms showed a better reliability for the products containing a singl e species whereas the ones composed of different strains were usually not satisfactory. In some cases, the presence of Lactobacillus and Sac charomyces species was in disagreement with the claimed composition of the product and some species of lactobacilli, bifidobacteria and stre ptococci were found not viable. In defined mixed cultures experiments, the antagonism of Lactobacillus acidophilus and Enterococcus faecium versus Yersinia enterocolitica was demonstrated and explained as acid and/or antimicrobials production.