ABSTRACT

This study evaluated the microbial communities in used and unused vegetable oil. In this study, the predominant microorganisms isolated were Bacillus sp, Staphylococcus aureus, Escherichia coli, Klebsiella sp, Pseudomonas sp, Aspergillus niger, Aspergillus flavus, and Penicillium sp. The total heterotrophic plate count (THPC) of the used vegetable oil ranged from 3.1 × 105cfu/ml to 4.8 × 105cfu/ml, while that of the unused vegetable oil ranged from 1.4 × 105cfu/ml to 3.0 × 105cfu/ml. The total coliform plate count (TCPC) of the used vegetable oil ranged from 3.1 × 105cfu/ml to 4.1 × 105cfu/ml, while that of the unused vegetable oil ranged from 1.1 × 105cfu/ml to 3.2 × 105cfu/ml. The total fungal plate count (TFPC) of the used vegetable oil ranged from 2.4 × 105cfu/ml to 3.9 × 105cfu/ml, while that of the unused vegetable oil ranged from 1.5 × 105cfu/ml to 2.9 × 105cfu/ml. it was observed that Staphylococcus aureus is the most frequently occurring bacteria isolate from the used vegetable oil sample with a percentage occurrence of (37.5%), followed by Bacillus sp with a percentage occurrence of (25.0%), then Escherichia coli, Pseudomonas sp and Klebsiella sp had the least percentage occurrence of (12.5%). In the same sequence, Pseudomonas sp is the most frequently occurring bacteria isolate from the unused vegetable oil sample with a percentage occurrence of (37.5%), followed by Bacillus sp and Staphylococcus aureus with a percentage occurrence of (25.0%) while Escherichia coli has the least percentage occurrence of (12.5%). The regulatory agencies in Nigeria should equally monitor microbial growth in oils meant for human consumption to avoid food poisoning and contamination. Therefore, more improvement is required in the production and distribution of vegetable oils in order to meet the stipulated standards. Statistical analysis showed that there were significant differences in mean count of the used and unused vegetable oil at P< 0.05