Potential Fate of Ingested Lactobacillus plantarum and Its Occurrence in Human Feces
ABSTRACTLactobacillusplantarumhas been used in human clinical trials to promote beneficial effects in the immune system, to alleviate intestinal disorders, and to reduce the risk of cardiovascular disease. It is also involved in many fermentation processes in the food industry. However, information on the fate of ingestedL. plantarumis limited. In this study, 61 subjects received daily doses of fermented milk containing 2 × 1011cells ofL. plantarumLp115 for different periods of time. The target microorganism was monitored in the fecal microbiota via quantitative PCR (qPCR).L. plantarumwas detected and quantified in all of the subjects during the ingestion periods. The differences between theL. plantarumlevels at time zero and during all the different ingestion periods were statistically significant (P= 0.001). However, at 15 and 45 days after discontinuing supplementation, the number of lactobacilli was reduced to the baseline level (those at time zero). A longer period withL. plantarumin the diet did not result in increased levels of this bacterium in the stool, based on postconsumption evaluations (P= 0.001). The qPCR method was specific and sensitive forL. plantarumquantification in such a complex microbial environment as the gastrointestinal tract.