International Journal of Applied Microbiology and Biotechnology Research
ISSN: 2053-1818
Vol. 9(3), pp. 51-62, June, 2021

Microbial analysis of packaged and exposed soybean flour sold in selected markets in Benin City, Nigeria

Ndukwe Maduka1*, Olise Blessing Egwali1 and Francis Sopuruchukwu Ire2

1Department of Biological Science, College of Natural and Applied Sciences, Wellspring University, Benin City, Edo State, Nigeria.
2Department of Microbiology, Faculty of Science, University of Port Harcourt, Port Harcourt, Nigeria.

*To whom correspondence should be addressed. E-mail:,

Received 05 May, 2021; Received in revised form 18 May, 2021; Accepted 26 May, 2021.


Soybean flour, Microbial analysis, Food additives, Exposed flour, Packaged flour.

Soybean flour is one of the products derived from processing soybean (Glycine max) popularly known for its rich protein content. It is usually exposed to microbial contamination during processing and handling which compromise food safety. In this study, microbial assessment of exposed and packaged soybean flour sold in four (4) markets in Benin City was carried out. A total of sixteen (16) samples which comprise of three (3) exposed and one (1) packaged soybean flour were randomly purchased from each market. Two (2) samples of soybean flour (sun-dried and oven-dried) prepared in the laboratory served as control. Analyses of all the samples were performed using Standard microbiological methods. The total heterotrophic bacterial count (THBC) of the exposed product obtained from Oba (OBM), Ogba (OGM), Uselu (USM) and New Benin (NBM) markets were within the range of 6.31-6.86, 0-6.66, 6.02-6.60 and 5.70-6.50 log10CFU/g while the equivalent values for total fungal count (TFC) were 0-4, 5.04-5.81, 4.90-5.18 and 4.48-5.27 log10CFU/g, respectively. The THBC of the packaged product obtained from OBM, OGM, USM and NBM were 6.51, 6.89, 6.54 and 6.73 log10CFU/g whereas the equivalent values for TFC were 5.76, 6.69, 6.72 and 6.43 log10CFU/g, respectively. A total of 25 bacterial and 13 fungal isolates were obtained from all the samples. The bacterial isolates and their percentage occurrence were Escherichia coli (12%), Klebsiella sp. (12%), Enterobacter sp. (20%), Citrobacter sp. (20%) and Bacillus sp. (36%) while the fungal isolates were Aspergillus niger (23%), Aspergillus clavatus (8%), Aspergillus nidulans (8%), Aspergillus flavus (15%), Aspergillus oryzae (8%), Saccharomyces sp. (8%), Penicillium sp. (15%), and Mucor sp. (15%). Two exposed soybean flour samples from OGM and the control met the THBC criteria recommended by International Commission on Microbiological Specification for Foods, while others did not. Therefore, proper packaging, personal hygiene practices and good manufacturing practices are recommended to guarantee that soybean flour available in the markets are safe for human consumption.

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