Bacterial diversity and community structure of some traditional African and European cereal-based fermented foods identified by high-throughput sequencing

Cereals are staple foods worldwide. They are often processed using spontaneous fermentation or backslopping. Many cereal-based fermented foods (CBFFs1) are produced in small-scale production units or at household level. Despite growing understanding of the bacterial communities involved in fermentation, many CBFFs remain little explored. A better understanding of these bacterial communities and of the impact of cereal, processing, and the geographical area is essential to harness the potential of their endogenous bacteria. This study investigated the bacterial communities of four traditional CBFFs originating from two African countries, Burkina Faso and Ethiopia, and one European country, Finland, using high throughput 16S rRNA sequencing. CBFFs made from pearl millet, rye and teff include bread, dumplings, pancake-like flatbread and porridge. Lactic acid bacteria (LAB2) dominated all four CBFFs, but their composition and abundance varied with the cereal, geography, and fermentation conditions. Potential pathogenic bacteria were observed, particularly in one CBFF after wet milling in small community milling units. Many LAB strains have properties which can improve health and nutritional status in population. The assessment of the functional properties of LAB isolated from these rarely studied CBFFs and their subsequent use would enable CBFFs with improved nutrient contents at low cost via controlled fermentation. This is of particular importance in Africa where household resources are often limited, but also in Europe where the preparation of homemade fermented foods is increasingly popular.