Molecular Characterization of Bacteria Associated with the Spontaneous Fermentation of Bambara Nut in “Ogirri”

Abstract

Fermentation is one of the oldest methods of food preservation known to man. Oil seeds and legumes have been fermented to give condiments. Molecular characterization of the bacteria associated with the spontaneous fermentation of Bambara nut (Vigna subterranea) seeds into “Ogirri” was carried out. Vigna subterranea seeds were subjected to pre-treatments of soaking and boiling and spontaneously fermented in 3 setups for a period of 96 h at 28±2 C to yield ogirri product. The isolates were identified using cultural and morphological methods, and the identities of the bacterial isolates were confirmed using molecular characterization techniques. The total microbial count showed an increase from 2.0 x 10  cfu/g at 0 h to 9.50 x 10  cfu/g at 96 h for the bacterial isolates while the fungal isolate increased from 1.30 x 10  cfu/g at 24 h to 6.30 x 10  cfu/g at 96 h. The identities of four out of five bacterial isolates were successfully confirmed as Bacillus cereus strain BTD4-2, Bacillus cereus strain GBPS9, Phyllobacterium leguminumstrain ORS1419 and Lysinibacillus fusiformis strain LMG 18474. The confirmation of the identities of the isolates from the spontaneous fermentation process showed that the product was predominantly fermented by species of the genera Bacillus. These organisms play a key role in the flavour development and influence the chemical composition of the fermented food through substrate modification.