Physicochemical and Microbiological Quality of Fresh and Smoked Catfish (Clarias gariepinus) and Tilapia (Oreochromis niloticus) in Ibadan, Nigeria

Aim: This study aimed to determine the microbiological quality of fresh and smoked Catfish (Clarias gariepinus) and Tilapia (Oreochromis niloticus) collected randomly from two fish markets (Asejire and Eleyele) and University of Ibadan fish farm.

Study Design: Microbiological analyses of the samples were done using standard microbiological procedures.

Place and Duration of Study: Fresh Catfish (Clarias gariepinus) and Tilapia (Oreochromis niloticus) species fish samples were collected at Eleyele, Asejire and University of Ibadan fish farm. All samples were collected randomly and placed in sterile polythene bags. The fresh fish samples were also collected in clean plastic containers and transported to the Postgraduate Laboratory of the Department of Microbiology, University of Ibadan for analyses.

Methodology: The fish samples were cultured and isolates were obtained from the flesh, gills and guts. The pH was determined by weighing 3g of the fish samples and the samples were washed in sterile distilled water. The fish samples were also analyzed to determine their proximate composition. The fish samples were analysed using standard microbiological procedures.

Results: A total of 90 bacterial isolates were obtained from the different fish samples with their bacterial count ranging from 1.0 × 102 – 5.0 × 105 CFU/g. The bacterial diversity were; Staphylococcus aureus, Salmonella sp., Shigella sp., Pseudomonas aeruginosa, Klebsiella pneumonia, Klebsiella oxytoca, Klebsiella ozaenae, Acinetobacter baumanii, Proteus vulgaris, Escherichia coli, Enterobacter aerogenes, Citrobacter freundii and Moraxella catarrhalis. A total of 51 fungal isolates were obtained also with the fungal counts ranging from 1.0 × 102 – 6.0 × 104 CFU/g. The three (3) species obtained from the samples were identified as Aspergillus sp., Fusarium sp. and Penicillium sp. The frequency of occurrence of the bacterial isolates was highest (27%) for Shigella sp. and least (1%) for both Proteus vulgaris and Pseudomonas aeruginosa.

Conclusion: In the current study the fish samples obtained from the different locations could be contaminated with pathogenic microorganisms and therefore Catfish and Tilapia fish should be properly washed, cooked and smoked before consumption.