Assessment of novel probiotic Lactobacillus casei strains strains for the production of functional dairy foods.

Selected Lactobacillus casei strains were examined for their potential use in new probiotic fermented milks by evaluation of their technological performances, in vitro adhesion capacity and intestinal transit tolerance after administration to rats. Serum, tissue and faecal samples were analysed before and during treatments. The number of intestinal lactobacilli increased significantly after administration of all four strains as verified by standard microbiological analysis and specific polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Lactobacillus casei strains were also detected by PCR in faecal samples and specimens of the intestinal epithelium after treatment. Electron microscopy of gut mucosa revealed a thickening of the glycocalyx covering the enterocytes. In all treated rats, levels of serum triglycerides, cholesterol, transaminase and total bilirubin decreased. Microbiological and haematological parameters indicated that all four L. casei strains present favourable strain-specific properties for their utilisation in functional, health-favouring food