Effect of fermentation of Ghanaian maize dough on the survival and proliferation of 4 strains of Shigella flexneri.

Fermented and non-fermented Ghanaian maize dough was seeded with approximately 10(7) colony forming units of 4 strains of Shigella flexneri which had been isolated from patients with dysentery. In the non-fermented maize dough (pH 6.2) the shigellae were detectable in large numbers for up to 24 h after exposure. In the maize dough that had been fermented for 3 d (pH 3.2) 3 strains were detectable in small numbers for up to 6 h after inoculation. Thereafter none was isolated. The fourth strain, though detectable for up to 24 h after inoculation, had its numbers reduced considerably. This suggests that traditional methods of food preparation using fermentation have important anti-diarrhoeal functions and the current decline in popularity of such food technologies in certain developing countries may increase the risk of childhood diarrhoea.