["To characterize mechanisms of hand contamination with faecal indicator bacteria and to assess the presence of selected pathogens on mothers' hands in Tanzania.", 'A household observational study combined with repeated microbiological hand rinse sampling was conducted among 119 mothers in Dar es Salaam, Tanzania. All hand rinse samples were analysed for enterococci and Escherichia coli, and selected samples were analysed for genetic markers of Bacteroidales, enterovirus and pathogenic E. coli.', "Using the toilet, cleaning up a child's faeces, sweeping, cleaning dishes, preparing food and bathing were all found to increase faecal indicator bacterial levels on hands. Geometric mean increases in colony forming units per two hands ranged from 50 (cleaning dishes) to 6310 (food preparation). Multivariate modelling of hand faecal indicator bacteria as a function of activities recently performed shows that food handling, exiting the household premises and longer time since last handwashing with soap are positively associated with bacterial levels on hands, while bathing is negatively associated. Genetic markers of Bacteroidales, enterovirus and pathogenic E. coli were each detected on a subset of mothers' hands."] Does bacterial hand contamination among Tanzanian mothers vary temporally and following household activities?