Effect of storage temperature on microbial safety of “Ogi”

Abstract

The microbiology of “Ogi” made from maize and sorghum purchased from two different markets in Uyo, Nigeria was determined using standard methods. The investigation was carried out on the “Ogi” samples under two storage conditions (refrigeration at 4°C and cold water steeping at room temperature 28°C, with the water being changed daily). Results showed that total aerobic plate count ranged from 1.00 to 2.03 x 10 cfu/g and 1.00 to 1.19 x 10 cfu/g for maize “Ogi” stored at 28°C and 4°C,
respectively.Total aerobic plate counts for sorghum “Ogi” ranged from 1.13 to 1.85 x 10 cfu/g at 28°C and 1.13 to 1.14 x 10 cfu/g, at 4°C storage.Total lactic acid bacteria (LAB) count was slightly higher than the aerobic plate count (APC) for both samples, ranging from 1.01 to 2.30 x 10 cfu/g and 1.01 to 1.99 x 10 cfu/g under steeped water (28°C) and refrigeration (4°C), respectively for maize “Ogi”. TheLABvalues for sorghum “Ogi” ranged from 1.18 to 2.01 x 10 cfu/g and 1.18 to 1.83 x 10 cfu/g for steeped water storage (28°C) and refrigeration (4°C), respectively. Statistical analysis using Analysis of variance (ANOVA) showed
that higher microbial counts of the samples at 28°C was not significant (p=0.05) from those at 4°C storage. Fungal counts were however lower than the bacterial counts in all samples tested being ~10 cfu/g. Organisms isolated included, Lactococcus spp, Lactobacillus spp, Staph aureus, Bacillus subtilis, Klebsiella oxytoca, Leuconostoc spp, Aspergillus spp, Fusarium spp, Penicillum spp, Cladosporium spp, Candida spp and many of which are associated with “Ogi” fermentation. The result of this study suggests that “Ogi” preserved by steeping in water at 28°C for up to 5 days, is microbiologically safe. This is encouraging to rural communities
where power supply needed for cold storage is unreliable. 

Keywords Storage temperature, microbiology, 'Ogi’