Lactococci dominate the bacterial communities of fermented maize, sorghum and millet slurries in Zimbabwe

Maize, sorghum and millet fermented porridges are important as complementary foods for young children in Africa. The objective of the present study was to gain some insights into the bacterial communities of fermented slurries prepared from maize, sorghum and millets originating from different locations in Zimbabwe, and prepared either at household or laboratory level. A deep sequencing approach targeting the hypervariable V4 region of the 16S rRNA gene was used and yielded about 100,000 sequences per sample. Lactococcus dominated all the fermented slurries, flanked by other lactic acid bacteria such as Weissella, Leuconostoc and Enterococcus. Enterobacteriaceae detected in the water samples persisted throughout all the fermented cereals. Other subdominant bacteria identified in the fermented slurries included Aeromonas, Pseudomonas and Acinetobacter. In addition, some Proteobacteria, Actinobacteria and Bacteroidetes associated with the raw materials and environment were also detected. Fermented slurries could not be differentiated based on their origin nor on the type of fermentation, but clear differences were observed between red sorghum fermented slurries and fermented slurries prepared from other cereal flours. A thorough understanding of the functional capacities of the microbiota in African fermented slurries is highly needed in order to steer the fermentation for the production of standard, safe and nutritious fermented products.