Full Length Research Paper
Microbiological quality of catfish (Clarias gariepinus) smoked with Nigerian Stored Products Research Institute (NSPRI) developed smoking kiln
Olayemi F. F., Raji A. O.2 Adedayo M. R.*3
Nigerian Stored Products Research Institute, PMB 3032, Kano, Kano State, Nigeria. Department of Agriculture and Environmental Engineering, University of Ibadan, Ibadan, Nigeria. 3* Microbiology unit, Biosciences and Biotechnology Department, College of Pure and Applied Sciences, Kwara State University, Malete, Nigeria.
The microbial quality of cat fish (Clarias gariepinus) smoked with Nigerian Stored Products Research Institute (NSPRI) developed smoking kiln was assessed. Raw fish samples were purchased and cleaned before smoking in the kiln designed and constructed by the institute. Potato dextrose agar and nutrient agar were used for the mould/yeast and bacteria load of the smoked fish respectively while appropriate selective media were used for the isolation of the enteric organisms. The total bacteria count was 2.0 x -4 -4 10 cfug and 0.7 x 10 cfug for mould/yeast. The result showed that no Pseudomonas, Escherichia coli or Salmonella species was found on the smoked fish. Generally the total bacteria count was higher than the mould/yeast count. The sensory evaluation of the smoked fish showed that the fish was generally acceptable in taste and flavour. In conclusion, C. gariepinus smoked with NSPRI developed smoking kiln is of high microbiological standard and suitable for human and livestock consumption. Keywords: Catfish, Smoking kiln, Bacteria, Mould, Yeast, Enteric organisms. INTRODUCTION The production and consumption of fish in Nigeria has been a major source of animal protein which has competed favorably with meat. Cat fish (Clarias gariepinus) has been reported to be a very important freshwater fish in Nigeria. It has enjoyed wide acceptability in most parts of the country because of its unique taste, flavor and good texture. It is widely distributed, extensively cultivated in ponds. Fish is one of the best sources of proteins, vitamins and minerals and are essential nutrients required for supplementing both infant and adult diets (Abdullahi et al., 2001). In Nigeria, it has also been noticed that fish is eaten fresh, preserved or processed (smoked) and form a much-cherished delicacy that cuts across socioeconomic, age, religious and educational barriers (Adebayo-Tayo et al., 2008). As earlier reported, the microbial flora associated with freshly harvested fish is principally a function of the environment in which the fish are caught and not of the fish species; hence, the indigenous microbial populations of fish can vary significantly (Shewan 1961). A similar report on fish confirmed that, fish because of their soft tissues and aquatic environment are extremely susceptible to microbial contamination. Millions of bacteria, many of them potential spoilers, are present in the surface slime, on the gills and in the intestines of live fish, although the flesh itself is normally sterile. Bacterial growth and invasion on the fish are prevented by the body’s natural defense system during life but after death the defense system breaks down and the bacteria multiply and invade the flesh (Abolagba and Uwagbai, 2011). Poor postharvest technology (handling, preservation and processing) have been reported earlier to have the ability to cause unhealthy situation resulting in massive spoilage. An estimate of 40% postharvest losses of total
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fish landings have been reported in Nigeria (Akande,1996). (Mayboom 1974) similarly reported that 15% of the