Influence of sunlight on the bacteriological quality of groundnut oil produced locally in Abuja, Nigeria

Abstract

Groundnut oil plays a critical role in nutrition and cooking within Nigeria. This study investigates the impact of sunlight on the bacteriological and proximate qualities of locally produced groundnut oil from Wuse, Kubwa, and Bwari in the Federal Capital Territory (FCT) Nigeria. Samples were collected and analyzed using standard methods and procedures. Percentage moisture content, ash content, protein and carbohydrate were high in the raw groundut oil when compared to the fried groundnut oil. Before exposure to sunlight the mean colony of bacteria was highest (5.60 ± 0.28 ×10^-3) in raw groundnut oil collected from Bwari market and was lowest (2.36 ± 0.18 ×10^-3) in fried groundnut oil collected from Kubwa market. After exposure to sunlight, the mean bacteria colony was highest (5.63 ± 0.12 ×10^-3) and lowest (3.46 ± 0.20 ×10^-3) in both raw and fried groundnut oil collected from Kubwa. A total of five bacteria species were isolated and identified from the unexposed and exposed oil samples and the identitied bacteria species are Escheriscia coli, Campylobacter sp. Salmonella sp.,Bacillus cereus and Staphylococcus aureus. The antibiotic susceptibility test shows that all bacteria isolates were sensitive to pefloxacin except Staphylococcus aureus. All the bacteria isolates were resistant to gentamycin except Bacillus cereus. All bacteria isolates were sensitive to ampiclox, chloranphenicol and ciprofloxacin. Overall, the results showed significant differences in the nutritional and microbial quality of oil depending on sunlight exposure and processing methods. This study highlights the importance of improved handling and storage practices to enhance food safety and oil quality.