Study design and top 15 abundant genera of the oral microbiota and probiotic yoghurt. (A) Samples of both members of recruited couples were collected of the anterior dorsal tongue surface and saliva prior to (blue) and after an intimate kiss of 10 s (red). One of the partners was asked to consume 50 ml of a probiotic yoghurt drink, and again tongue and saliva were collected of the donator prior to (yellow) and the receiver after a second intimate kiss (green). (B) Relative abundances of the top 15 most dominant genera of the oral microbiota and probiotic yoghurt plotted on a log transformed color-coded rainbow scale from 0 to 12 from black, blue, green, yellow, orange to red. Headers include partner, probiotic yoghurt drink, saliva, tongue, sample IDs, couples, and sample type, as indicated by the same color-coding in the study design.