Comparative Microbial Quality and Safety of Fresh, Oven-Dried, and Sun-Dried Okra (Abelmoschus esculentus)

Abstract

This study evaluated fresh, oven-dried, and sun-dried okra (Abelmoschus esculentus) to determine the effect of different drying methods on its microbial quality and nutritional composition. Fresh okra samples were collected from the Department of Agriculture, University of Port Harcourt, and processed into three groups: fresh (control), oven-dried at 60 °C for 8 to 12 hours, and sun-dried for seven days. Microbial enumeration was conducted using standard methods. Physicochemical analyses included the determination of moisture, crude protein, fiber, lipid, and ash contents using standard AOAC methods. Results revealed that the total heterotrophic bacteria count ranged from 6.68 to 6.81 log₁₀ CFU/g, with the highest count observed in fresh okra and the lowest in oven-dried samples. Total coliform counts ranged from 3.28 to 6.70 log₁₀ CFU/g. Staphylococcus counts (6.13–6.65 log₁₀ CFU/g) and fungal counts (5.45–5.63 log₁₀ CFU/g) also showed marked reductions after oven drying compared to sun drying. The predominant bacterial isolates included Bacillus, Pseudomonas, Klebsiella, Serratia, Enterobacter, and Staphylococcus species, while Aspergillus, Fusarium, and Penicillium were the main fungal isolates. Proximate analysis indicated that drying significantly reduced moisture content (fresh > sun-dried > oven-dried), while increasing ash (1.85 → 5.05%) and fiber (0.18 → 3.15%) contents. In contrast, protein (4.30 → 2.03%) and lipid (1.93 → 0.96%) levels decreased after drying. The results demonstrate that oven drying was more effective than sun drying in reducing microbial contamination while maintaining acceptable nutrient composition. However, microbial counts in some samples exceeded international safety limits, underscoring the need for strict hygienic handling and controlled drying conditions to ensure the microbial safety and nutritional quality of dried okra products.