In vitro investigations of the effect of probiotics and prebiotics on selected human intestinal pathogens

This study investigated the effects of selected probiotic microorganisms, in combination with prebiotics, on certain human intestinal food-borne pathogens. Probiotics grown with different carbohydrate sources were observed to inhibit growth of Escherichia coli, Campylobacter jejuni and Salmonella enteritidis, with the extent of inhibition varying according to the carbohydrate source provided. Prebiotics identified as being preferentially utilised by the probiotics tested were oligofructose (FOS), inulin, xylo-oligosaccharide (XOS), and mixtures of inulin:FOS (80:20 w/w) and FOS:XOS (50:50 w/w). Two of the probiotics. Lactobacillus plantarum and Bifidobacterium bifidum were selected for further co-culture experiments. Each was combined with the selected prebiotics, and was observed to inhibit pathogen growth strongly. Results suggested that acetate and lactate were directly conferring antagonistic action, which was not necessarily, related to a lowering of culture pH. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.