Microbiological and Proximate Composition of Different Stored Wheat Flour Brands Sold in Uyo Metropolis, Nigeria

Abstract

To determine the microbiological quality of wheat, three brands (Golden penny, Honeywell and Home-made) of wheat flour were subjected to proximate and microbiological analysis in triplicates using standard methods. The mean moisture values for the brands were 8.60 ± 0.03% for WPP, 10.30 ± 0.12% for WHW and 10.50 ± 0.06% for WGP, while the mean ash content values for the brands were 1.41 ± 0.12% for WGP, 1.56 ± 0.13% for WHW and 2.06 ± 0.05% for WPP. Mean bacterial loads ranged between 1.39 ± 0.12 and 4.5 ± 0.05 log cfu/g and the mean fungal loads ranged between 1.83 ± 0.18 and 4.0 ± 0.16 log cfu/g. There was significant difference (p≤0.05) in both the bacterial and fungal counts in all the brands during storage. The microorganisms isolated from all the wheat flour brands and their percentage of occurrence were Bacillus cereus (22.5%), Acetobacter spp. (20.4%), Micrococcus luteus (20.4%), Penicillium spp. (10.2%), Aspergillus niger (8.2%), Aspergillus fumigatus (6.1%), Alternaria alternata (6.1%) and Fusarium oxysporum (6.1%). Increase in microbial load positively correlated with high moisture content and storage period. The pH values in all the brands showed significant difference at p≤0.05 throughout the storage period but no significant difference between pH values of each of the brands. The microbial loads were within the allowable limit for cereal foods, therefore consumption of the analysed brands of wheat may not pose a health risk to consumers especially when properly cooked before consumption.