Fomites　are　known　to　spread　infectious　diseases,　but　their　role　in　determining　transmission　risk　remains　unclear.　The　association　of　surface　touch　networks　(STNs),　proposed　to　explain　this　risk,　with　real-life　surface　contamination　has　not　yet　been　demonstrated.　To　construct　STNs,　we　collected　surface　touch　data　from　23　to　26　scholars　through　2　independent　experiments　conducted　in　office　spaces　for　13　h　each.　In　parallel,　a　tracer　bacterium　(Lactobacillus　bulgaricus)　was　spread　by　a　designated　carrier　in　each　experiment　during　normal　activities;　the　subsequent　extent　of　surface　contamination　was　assessed　using　qPCR.　The　touch　data　were　also　analyzed　using　an　agent-based　model　that　predicted　the　observed　contamination.　Touching　public　(door　handles)　and　hidden　public　(desks,　chair　seatbacks)　surfaces　that　connected　occupants,　sparse　hand-to-hand　contact,　and　active　carriers　contributed　significantly　to　contamination　spread,　which　was　also　correlated　with　the　size　of　the　social　group　containing　carriers.　The　natural　and　unsupervised　experiments　reflected　realistic　exposure　levels　of　mouths　(1-10　ppm　of　total　contamination　spread　by　one　root　carrier),　nostrils　(-1　ppm),　and　eyes　(-0.1　ppm).　We　conclude　that　the　contamination　degree　of　known　and　hidden　public　surfaces　can　indicate　fomite　exposure　risk.　The　social　group　effect　could　trigger　superspreading　events　through　fomite　transmission.