Microbial Profile of Fermented Maize Flour (Ogi) and African Oil Bean (Pentaclethra macrophylla) Seeds

Abstract

This study assessed the microbial and physicochemical properties of fermented maize flour (Ogi) and Pentaclethra macrophylla seeds (Ugba). The microbial analyses were done based on microbiological standards. The samples were monitored at points of preparation from 0 to 96 hours of fermentation. The physicochemical parameters were performed in accordance to standard procedures. Selected dilutions were inoculated by pour-plate method on appropriate media for isolation of aerobic bacteria, Staphylococci, coliforms, lactic acid bacteria (LAB) and fungi. Molecular identification of the LAB were done using 16s rRNA Sanger sequencing method. The pH decreased steadily from 3.9 to 3.3 for Ogi and from 7.7 to 5.8 for Ugba, with a corresponding increase in titratable acidity from 1.3 to 2.5 for Ogi and from 0.6 ± 0.14ef to 1.2 ± 0.28c for Ugba. Microorganisms isolated from fermented maize flour (Ogi) and ‘Ugba’ were; Lactobacillus brevis, L. plantarum, Pediococcus acidilactici, Staphylococcus species, Escherichia coli, Bacillus species, Micrococus species, Pseudomonas species, Proteus species, Saccharomyces species, Aspergillus species and Candida species. The total bacteria counts showed decrease in both samples, with Ugba having the highest bacteria count (2.7×106±12.00a cfu/g which decreased to 1.0×106 ± 2.00f cfu/g) compared to Ogi with values (1.3×106 ± 3.00c cfu/g to 1.6 ×105± 1.73h  cfu/g) from 0 hour to 96 hours of the fermentation period. Fungi counts increased in both samples throughout the fermentation period with Ugba having counts of (1.4 ×103± 2.65i to 2.8 ×104 ± 5.00 a cfu/g), and Ogi (7.7 ×103± 1.53 h to 2.7 ×104± 6.00 b cfu/g). LAB were persistent and most predominant in Ogi while Bacillus species were most predominant in Ugba. The variations in their different levels of values were of significant difference (P ≤ 0.05). This study revealed the distribution of fermentative microorganisms and few contaminants which were not directly associated with fermentation process and that can however, be further reduced through heat preparation treatment of Ogi.