Abstract

Catfish (Clarias buthupogon) was treated with 10% w/w NaCl and 15% w/w NaCl with or without the addition of spices (1% w/w garlic powder and 1% w/w red pepper) and allowed to ferment naturally and at room temperature (28 ± 2°C) for two weeks. Bacterial, chemical and sensory analyses were carried out on the unfermented non-salted and fermented salted samples of the fish species. Results obtained revealed that fermentation and salting caused a remarkable reduction in the total bacterial count from 2.29×10⁶ to 3.80×10⁵ cfu/g. There was also reduction in pH from 7.29 to 5.26. The predominant bacteria isolated from the samples were Lactobacillus sp, Staphylococcus spp for the unfermented non salted and fermented salted samples respectively while total titratable acidity increased from 0.63 to 1.44%. Chemical analysis result showed that fat and ash contents increased with fermentation and salting while moisture, protein and Nitrogen free Extracts (NFE) contents decreased with fermentation and salting of C. buthupogon. Free fatty acid, peroxide value and total volatile base (TVB) also showed increase with fermentation. Peroxide value ranged from 5.22 mEq/kg for unfermented non-salted to 8.43 mEq/kg for fermented 15%w/w salted products while total volatile base increased from 5.63 mgN/100 g unfermented non-salted to 16.85 mgN/100 g for fermented 10%w/w salted products. Sensory analysis indicates that stew containing fermented samples treated with 10%w/w NaCl and spices were more preferred than others.

Key words: Catfish, microbial, chemical, sensory, marinate, fermentation.