In this study, we combined microbiological analyses; spot-check observations and in-depth interviews to study food safety in small restaurants in Antananarivo (Madagascar). We showed that faecal contaminations (Escherichia coli, Salmonella spp.) occur at high rate in mixed salad sold in these restaurants. This is resulting from vendors' unhygienic behaviours. We studied vendors' motivations and priorities as well as their material and social context of activity. Based on our findings, we propose key elements to build intervention programmes to promote an appropriate culture of food safety: (i) using disgust associated with the contact with stools to explain contamination chains of food and water; (ii) emphasizing on vendors' representation of the link between cleanliness and health together with changing norms about what is seen as "clean"; and (iii) emphasizing on vendors' responsibility towards customers' health using the Malagasy traditional ideology of "tody".