The Determination of Shelf Life and Some Nutritional Components of Catfish (Clarias lazera) After Hot Smoking

Changes in the quality of hot smoked catfish Clarias lazera were determined just after smoking and during refrigerated storage (4°C±1). Chemical, sensory and microbiological analyses of the samples were carried out during the storage to test their shelf life and quality. Significant (p 0.05) differences were found in the chemical composition of fresh and smoked Clarias lazera. The process reduced moisture content and pH and increased crude protein, crude fat and ash. During storage at 4°C±1 the percentage of total protein, the ash contents and the pH increased significantly (p 0.05), whereas the moisture contents and the crude fat significantly (p 0.05) decreased. Microbiological analysis results demonstrated that the smoking techniques reduced the microbial content of the fish; total viable counts (TVC) of bacteria in fresh fish used as raw material had a total microbial load reaching 19.6×106 cfu/g. After smoking, TVC recorded 3.2×106 cfu/g and pathogenic micro-organisms Escherichia coli were counted about 3.8×106 cfu/g, therefore Salmonella spp and Staphylococcus aureus were not detected in the fish samples. No yeast or mould was detected in the fresh and smoked samples. During storage at 4°C the weekly change in microbial loads of smoked C. lazera were increased, micro-organisms E. coli and Salmonella spp were observed, while Staphylococcus aureus were not detected. Sensory evaluation of smoked fish samples showed that the quality of the smoked fish might still be acceptable 28 days after smoking under refrigerator conditions.