The present invention relates to a prebiotic composition comprising a microbially produced oligosaccharide, wherein the oligosaccharide is characterised by being selective for a pre-determined probiotic bacterial strain and also capable of being produced by the pre-determined probiotic bacteria by reverse enzyme action. The present invention also relates to methods of screening a composition suitable for use as a prebiotic and methods for screening of prebiotics for incorporation into synbiotic formulations.
