Sensory survey of key compounds of toilet malodour in Switzerland, India and Africa

Abstract

Improving sanitation in developing countries is a key issue. New toilets must be clean and well maintained and must present a pleasant olfactory experience. Knowledge about toilet malodour is crucial to create pleasant perfumes for toilets. To identify the key constituents of toilet malodour, we created synthetic reconstitutions based on our previous analytical work, and we performed sensory surveys in Switzerland, India and Africa to evaluate the efficiency of our synthetic reconstitutions made of selected key compounds to evoke toilet malodor. The olfactory stimuli were two reconstitutions of faecal odours and a reconstitution of stale urine odour. We also used three perfumes as controls: banana, lemon and lavender. Participants from Geneva (N=21, Switzerland) and from the slums of Ahmedabad (N=105, India), Nairobi (N=143, Kenya) and Durban N=144, South Africa) were familiar with all odours presented. They described banana, lemon and lavender as pleasant odours and both faecal reconstitutions and stale urine reconstitution as unpleasant odours. Faecal reconstitutions were identified as odours that emanate from faeces or latrines in all countries. These results confirm and consolidate those of previous studies on faecal odours in identifying butyric acid, p-cresol, indole and dimethyl trisulfide as strong contributors to human faecal odour.