Zeitschrift für Lebensmittel : Mikrobiologie, Sicherheit und Hygiene
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Abstrakt

Dynamics of Microbial Populations on Fermented Nigerian

Babatuyi CY, Boboye BE and Ogundeji BA

Representative grains of Nigerian local (Igbemo) rice obtained from Akure, Nigeria were cooked and fermented under aseptic conditions for seven days. Fungi and bacteria associated with the sample before and during the fermentation were isolated and characterized. The pH and sensory attributes of the rice samples were also determined as fermentation progressed. Among the diverse bacteria isolates obtained from the food, only Bacillus cereus and B. subtilis were isolated consistently with populations that ranged between 1.0 × 10³-1.9 × 10⁴ cfu/g. Others were B. megaterium, B. maceans, B. polymyxa, B. brevis, Erwinia amylovora and E. tracheiphila. The following fungi isolates were obtained from the rice before and during fermentation: Vigaria nigra, Varicoporium elodeae, Articulospora inflata, Penicillin italicum and Saccharomyces cerevisiae. While the first three were only isolated within the first day of fermentation, the fourth (P. italicum) with population range of between 2.0 × 103-3.0 × 103 sfu/g occurred till the third fermentation day. Saccharomyces cerevisiae (5.0 × 10³-2.3 × 10⁴ sfu/g) was however isolated on the second to seventh fermentation days. Also, as the fermentation progressed, pH of the rice sample decreased but increased on the seventh fermentation day. There were no noticeable improvements in the appearance and aroma of the rice as fermentation progressed. The fermented rice was most palatable and generally acceptable on the seventh day of fermentation, thus making it ideal for consumption at the stage. Further research need to be conducted to determine the food’s nutritive status as fermentation progresses.