Microbiological Analysis and Molecular Characterization of Bacterial and Fungal Isolates Present in Exposed and Packaged Cassava, Plantain and Yam Flour Sold in Selected Markets in Port Harcourt, Rivers State, Nigeria

Abstract

In Nigeria, increasing cases of food borne diseases especially diarrhea reported by many families has been linked to consumption of microbial contaminated flour based meals. Exposed and packaged cassava, yam and plantain flour are locally available in our markets. In this study, standard microbiological methods were used to isolate and identify bacterial and fungal isolates from the flour samples. Further characterization of the isolates was done using molecular methods. Our results shows that Bacillus sp. (46.67 %), Staphylococcus sp. (40 %), Escherichia coli (10 %) and Salmonella sp. (3.33 %) is the percentage frequency of occurrence of bacterial isolates; Microsporum audouinii (14.08 %), M. canis (2.82 %), M. nanum (5.63 %), Exserohilum sp. (9.86 %), Trichoderma sp. (7.04 %), Candida tropicalis (5.63 %), C. rugosa (9.9 %), C. krusei (2.82 %) C. glabrata (5.63 %), Aspergillus fumigatus (4.23 %), A. flavus (1.41 %), A. terreus (2.83 %), A. versicolor (1.41 %), A. clavatus (2.82 %), A. niger (5.63 %), Phaeoacremonim sp. (1.41 %), Epicoccum sp. (2.82 %), Exophiala dermatitidis (1.41 %), Penicillium sp. (1.41 %), Cokeromyces sp. (2.82 %), Aureobasidium sp. (1.41 %), Rhodotorula sp. (2.82 %), Fonsecaea pedrosoi (1.41 %) and Phoma sp. (2.82 %) are percentage frequency of occurrence of fungal isolates. Molecular characterization revealed the bacterial isolates to be Bacillus megaterium strain WSH10 16S, Enterobacter sp. strain HZ21, Alcaligenes feacalis strain CGAPGPBS and Acinetobacter junii strain SB132 while the fungal isolates are Aspergillus niger strain NI26, Paecilomyces sinensis strain Gr133 and Tramestes polyzona strain CNRMA14.236. It is recommended that edible flours should be produced under strict hygienic condition and packaged to prevent microbial contamination of the products.