Profiling of Microbial Content and Growth in Fermented Maize Based Products From Western Kenya

Abstract

In most parts of Africa, the process of fermentation is not controlled and does not adhere to good manufacturing practices, therefore spoilage and pathogenic microorganisms can alter the quality of the end product and may cause foodborne illness. Traditional fermented products are mostly processed in an environment which creates a selection of microorganisms that produce the desired end product. In an attempt to find Lactobacilli which have probiotic properties and can be used in the development of starter culture for controlled fermentation of cereal products, the microbial populations of maize flour, overnight soaked dough, fermented cooked porridge, Mkarango and Busaa were enumerated and the inherent lactobacilli isolated. The microbial and biochemical profiles of the 6 days spontaneous Mkarango fermentation process were determined. The total viable count was 6.93 log cfu/g for fermented cooked porridge, 7.70 log cfu/g in Mkarango and 8.58 log cfu/g for Busaa. Lactobacilli counts were higher in maize flour with 7.43 log cfu/g while Enterobactericeae were lower in Mkarango. The highest moulds and yeasts counts were observed for Busaa, 7.25 log cfu/g. The lactobacilli isolates from fermented maize based products from western Kenya were predominantly Lactobacillus fermentum and Lactobacillus Plantarum. During fermentation time, Lactobacilli increased from 6.62 to 12.46 log cfu/g after 3 days of fermentation. From day 4, an increase in moulds and yeast count was observed, varying from 8.42 to 10.53 log cfu/g. Enterobactericeae count decreased from 5.99 log cfu/g on day 1 to less than 1 log cfu/g on day 6. Titratable acidity increased from 0.32% to 0.73% on day 5. Inversely, the pH of Mkarango decreased sharply from 6.64 to 3.64 on day 5 and slightly increased on the last day of fermentation. The microbial status of finished fermented maize based products is predominated by Lactobacilli and their isolates are predominantly Lactobacilli especially Lactobacillus fermentum and Lactobacillus Plantarum though further molecular tests are needed to confirm the species.