The microbiology of Kocho: An Ethiopian Traditionally Fermented Food from Enset (Ensete ventricosum)
Keywords:Enset, fermentation, Kocho, lactic acid bacteria, yeast
Kocho is starchy food product obtained from a mixture of the scraped pulp of pseudo stem and pulverized corm of enset plant (Ensete ventricosum). Ensete ventricosum is a drought resistant plant and can be cultivated as an alternative food source for food security problem around the globe. This study was conducted to examine the fermentation process, the microbial dynamics and the physicochemical changes that occur during traditional fermentation of kocho. Survey on kocho fermentation was carried out at three localities in the vicinity of Hawassa city, Southern Ethiopia. Matured enset plants were purchased and processed and fermented following the traditional methods practiced by the Sidama (local people living in and around Hawasa City) women. Kocho samples were taken for microbiological and physicochemical analysis. The fermentation process was conducted in two Phases: Phase I (surface fermentation or without burring) and Phase II (pit fermentation or buried in pit) under five treatment conditions (kocho dough with traditional starter culture in bucket at surface or not buried in the pit, Kocho dough without traditional starter in bucket at surface or not buried, kocho dough with traditional starter culture in bucket buried in the pit, kocho dough without traditional starter culture in bucket buried in the pit and traditional kocho fermentation in pit). At Phase I, Aerobic mesophilic counts (AMC) were varied between 3.8 and 7.8 log CFU/g in all treatments. Correspondingly lactic acid bacteria (LAB) and yeasts were varied between 2.3 to 9.5 and 2.1 to 8.3 log CFU/g respectively. The pH value ranged from 6.12 to 4.50. At Phase II, AMC showed decreasing trend and enterobacteriaceae were totally inhibited towards the end as pH value lowered. Inconsistent variation was observed on LAB and yeast counts. Results suggested that LAB and yeasts were identified as the major microorganisms responsible for the fermentation of kocho. The isolates need further investigation to identify to species and/or strain level and use in starter culture development.