Chemical and microbial properties of kiln-smoked catfish in selected locations in Ilorin Metropolis, Nigeria

Abstract

The use of smoking kiln for drying catfish is on the increase in Nigeria due to its effectiveness in reducing moisture and contamination with toxic compounds during smoking. Chemical properties of kiln-smoked catfish in selected locations in Ilorin metropolis were determined in this study. Kiln-smoked catfish were obtained from four major locations (Oyun, Asa-Dam, Tanke and Agbo-Oba) in Ilorin, Nigeria. The samples were subjected to chemical and polycyclic hydrocarbon content analyses. Dried catfish from all the locations had low moisture and crude fibre contents. There were no significant differences (p>0.05) in the crude fibre contents of the kiln-smoked catfish. Protein contents ranging from 53.72-56.49% were obtained for the kilnsmoked catfish samples. Fat contents ranged from 9.92-11.77% while the carbohydrate contents ranged from 19.02-23.59%. Potassium was the most abundant mineral in the samples with no traces of lead and cadmium. Agbo-Oba samples contained the highest pyrene (2983.215 ng/ml) and total polycyclic hydrocarbon (PAHs) (3349.090 ng/ml). Data on steroid fractions indicated that 17b-estradiol was significantly greater in quantity than those recorded from other steroid fractions. Microbial analyses of the samples revealed the presence of the following pathogenic organisms: Klebsiella spp, Salmonella spp, Shigella spp, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Vibrio spp, Aspergillus niger, penicilium spp, Trichoderma spp which are harmful to man. The use of smoking kiln method improved the nutrients and reduced PAHs in catfish.

Keywords: Smoking kiln, Catfish, Chemical properties, Polycyclic hydrocarbon, Mineral elements