Microbiological dynamics involved in cereal-porridge production using maize and sorghum

Francis S Ire Francis S Ire,Bernard Jo Efiuvwevwere Bernard Jo Efiuvwevwere,Mercy M Umokaso Mercy M Umokaso

doi:10.30574/gscbps.2022.18.1.0369

Francis S Ire Francis S Ire, Bernard Jo Efiuvwevwere Bernard Jo Efiuvwevwere + Show 1 more

Open Access

https://doi.org/10.30574/gscbps.2022.18.1.0369

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Abstract

Cereal-porridge(‘ogi’) was produced by spontaneous fermentation using maize and sorghum substrates. The microbiological dynamics involved were monitored over a period of 48h fermentation. Bacteria, yeasts and moulds were isolated. Based on the morphological, cultural and biochemical test results, the aerobic bacterial isolates were identified as Proteus vulgaris, Proteus mirabilis, Klebsiella sp, Staphylococcus aureus, Lactobacillus sp, Pseudomonas sp, Citrobacter sp, Bacillus sp, Proteus sp, Shigella sp, and Escherichia coli. The Lactic acid bacteria were Lactococcus sp, Enterococcus sp, Lactobacillus fermentum, Lactobacillus sp. The yeast isolates were 2 strains of Saccharomyces cerevisiae, one other Saccharomyces sp and a Candida sp. The moulds were Aspergillus niger, Aspergillus flavus, Rhizopus sp and Penicillium sp. The lactic acid bacteria (LAB) isolated were 2 strains of Lactococcus lactis, 2 Enterobacter spp, 5 strains of Lactobacillus fermentum and 1 other Lactobacillus sp. The initial total viable aerobic bacterial count at 0h in maize, sorghum and maize-sorghum blend were 4.6 × 104, 7.3 × 104 and 2.4 × 105cfu/ml respectively. The growths rose to peaks of 6.5 × 107 and 3.9 × 107cfu/ml at 24h in maize and maize-sorghum blend, respectively. A Peak of 4.7 x 107cfu/ml was attained at 36h in sorghum. Coliform bacteria and moulds growths in the three samples attained peaks of growth at 12h and reduced till there was no growth by 48h. Lactic acid bacteria and yeasts increased in numbers till the end of fermentation. The initial pH value at 0h was lowest in maize-sorghum blend sample (5.43) and highest in maize (5.75). Final values at 48h were 3.76, 3.78 and 3.75 in maize, sorghum and maize-sorghum blend samples respectively. There were no significant differences between the microbial growth patterns, changes in pH, total titratable acidity (TTA) and amylase enzymatic activities in maize, sorghum and maize-sorghum blend samples during fermentation.

Highlights

Microorganisms play dual roles in food products, especially during storage and processing
The food products produced is as a result of the type, age and the composition of the microorganisms employed
Changes in Viable Aerobic Bacterial Counts during Fermentation The results showed that the freshly prepared paste samples contained a high bioload

Summary

Introduction

Microorganisms play dual roles (beneficial and harmful) in food products, especially during storage and processing. The food products produced is as a result of the type, age and the composition of the microorganisms employed. Microbial populations and diversity play a role in the products of fermentation. ‘Ogi’ is a traditional fermented cereal-porridge consumed on a large scale among the low- income group in Nigeria, especially the nursing mothers, convalescent and weaning infants. It is usually produced by soaking of maize, sorghum or millet, followed by blending, sieving and the fermentation of the starchy cake. The traditional fermentation process occurs as a result of microbial inoculation from the environment [1, 2]

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