Comparative Preservative Effect of Garlic and Onion Pastes on Treated Smoke-Dried Oreochromis niloticus

Akpotu OJ, Obugara J and Udi MJ

Published on: 2025-05-17

Abstract

Fish is an important source of animal protein, but it is highly prone to spoilage due to microbial growth and enzymatic activity. The preservation of fish products is essential for maintaining quality and extending shelf life. This study investigates the comparative preservative effects of garlic (Allium sativum) and onion (Allium cepa) pastes on smoke-dried Oreochromis niloticus (Nile tilapia). Freshly smoked fish samples were treated with varying concentrations (5g, 10g, 15g, and 20g per 100g of fish) of garlic and onion pastes, while a control group remained untreated. The samples were stored at room temperature (25±2°C) and monitored over 14 days for microbial growth and sensory attributes. Microbial analysis revealed that garlic and onion pastes significantly inhibited bacterial proliferation, with higher concentrations demonstrating greater efficacy. Garlic paste at 20g exhibited the strongest antimicrobial effect, reducing microbial load to 8.0×10⁴ CFU/g by day 14 compared to 2.1×10⁵ CFU/g in the control. Sensory evaluation using a 9-point hedonic scale showed that fish treated with garlic and onion pastes maintained higher acceptability scores than the control, with garlic-treated samples demonstrating superior preservation. Statistical analysis (ANOVA, p<0.001) confirmed significant differences in microbial load and sensory attributes across treatments and storage days. The findings suggest that garlic and onion pastes, particularly at higher concentrations, can effectively enhance the shelf life and sensory quality of smoke-dried Oreochromis niloticus, with garlic exhibiting slightly superior preservative properties.