Antimicrobial Effects of Bay Leaf (Laurus nobilis) and Sesame (Sesamum indicum) Essential Oils on Dried African Catfish (Clarias gariepinus) During Storage in North-Central Nigeria

Contamination and postharvest losses determine the availability of fish in marketplaces and have raised public health concerns regarding their quality. We examined the antimicrobial effects of bay leaf (Laurus nobilis) and Sesame seed (Sesamum indicum) oils in preventing deterioration and extending the shelf life of African catfish (Clarias gariepinus). Sixty pieces of freshwater catfish were selected from different spots along the River Niger by randomised mixed sampling method and weighed (26 kg). These samples were divided into three equal (8.6 kg) groups (A, B & C) based on their method of drying: sun-dried (4.2 kg), smoked using firewood (3.9 kg), or smoked in a smoking kiln (3.8 kg). Isolation and identification of spoilage pathogens were performed using selective media, wet preparations, and molecular characterisation before and after drying. Essential oils of Laurus nobilis and Sesamum indicum were extracted through cold press and Soxhlet extraction methods and used at 0.02 mL/g of the fish to coat the dried catfish for preservation. Aliquots from the preserved fish were examined through serial dilution every month for three months. Essential oils from bay leaf inhibited microbial growth and preserved the stored catfish samples better than Sesame seed oil and ordinary drying methods, with microbial reduction count 3.1x103CFU/g against 4.0x103 CFU/g of sesame oil and 11.3x103 CFU/ g of the control; hence, it is recommended for preservation of dried fish. Key words: Effects, Essential Oils, Postharvest, Catfish, Nigeria.