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

Herve Mwizerwa^1,5*, George Ooko Abong^1*, Samuel Kuria Mbugua¹, Michael Wandayi Okoth¹, Patrick Gacheru¹, Maina Muiru², Brenda Obura³, Bennie Viljoen⁴

¹Department of Food Science, Nutrition and Technology, University of Nairobi, P. O. Box 29053-00625, Nairobi, Kenya

²Department of Plant Science and Crop Protection, University of Nairobi, P. O .Box 29053-00625, Nairobi, Kenya
³Ministry of Public Health and Sanitation, P. O. Box 30016-00100, Nairobi, Kenya
⁴Department of Microbial, Biochemical and Food Biotechnology, P. O. Box 339, Bloemfontein, University of Free State, South Africa
⁵National Agricultural Export Development Board, P.O Box: 104, Kigali, Rwanda.

Corresponding Author Email: mwizerwaherve@gmail.com

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 Busaawere enumerated and the inherent lactobacilli isolated. The microbial and biochemical profiles of the 6 days spontaneous Mkarangofermentation 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 forBusaa. Lactobacillicounts were higher in maize flour with 7.43 log cfu/g whileEnterobactericeae were lower in Mkarango.The highest moulds and yeasts counts were observed forBusaa, 7.25 log cfu/g.The lactobacilli isolates from fermented maize based products from western Kenya were predominantly Lactobacillus fermentum andLactobacillus Plantarum.During fermentation time, Lactobacilliincreased from 6.62 to 12.46 log cfu/gafter 3 daysof 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 Mkarangodecreased 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 andLactobacillus Plantarumthough further molecular tests are needed to confirm the species.

Fermentation; Lactobacilli; Maize based products; Microbial profile.

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