ABSTRACT

Ogi is a cereal gruel prepared by the fermentation of maize (Zea mays) grains. Bacteria isolated from the fermenting maize substrate (medium) were Staphylococcus aureus, Streptococcus spp, Lactobacillus spp, Bacillus spp and C'orynebacteiiu,n spp. Fungi isolated include the molds, Penicillium spp, Fusarium spp and Aspergillus niger, and the yeast Saccharoniyces spp. Total viable bacterial counts (on Nutrient Agar, NA) during the fermentation of Yellow Maize (YM) ranged from 2.00 x 101 to 2.35 x i07cfumi' and from 2.30x 10' to 3.35 x cfum1' for White Maize (WM). Total viable lactobacilli count (on de Mann Rogosa,,Sharpe Agar, MRSA) during the fermentation of YM ranged from 1.10 x 10' to 6.55 x 106 cfumF' and from 1.40 x 10' to 7.40 x 106 cfuml for WM. Total fungal counts on Sabouraud Dextrose Agar (SDA) during the fermentation of WM ranged from 1.30 x 10' to 2.75 x 106 cfuml arid from 1.00 x 101 to 2.55 x 106 cfumf' for YM. pH and temperature varied with time and were influenced by the metabolic activities of the micro-organisms. Variations in the microbial groups show that Lactobacillus spp, Streptococcus spp, and Saccharomyces spp were the most prevalent micro-org1nisms and occurred until the end of the fermentation. The percentage of titratable acidity for both maize varieties appeared to increase as fermentation progressed in relation to the fall in pH; the final values for WM and YM varieties are 0.45% and 0.44% respectively.