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INTRODUCTION
The abundance of fish along the coast of Namibia is a natural resource that forms part of the backbone of the country‟s economy. In order to maintain and grow its market share compliance with various international food safety guidelines is essential (Scharm, 1998). It is therefore important to monitor the microbiological parameters of harvested marine fish to ensure that the product does not pose health hazards to end users and that the levels of potential spoilage organisms is within the limits that permit acceptable product shelf life.
Sea food spoilage occurs mainly as a result of bacterial metabolism of the fish muscle producing metabolites that decrease the quality of fish. The most common spoilage reaction is the production of biogenic amines of which trimethylamine is the most important (Gram and Huss, 1996; Kyrana and Lougovois, 2002). In terms of safety, human pathogenic Vibrio species are of great concern (Nilsson and Gram, 2002; Wekell et al., 1994). These pathogens are common inhabitants of the natural marine environment and may enter the final product via contamination from processing equipments and surfaces, food handlers or via water used in the processing plant (DePaola et al., 2000; Joseph et al., 1982).The situation might be aggravated when quality assurance and quality control tests fail to correctly identify the pathogens due to atypical genetic or phenotypic traits hence conferring a false sense of security (Farmer et al., 2004; Oliver and Kaper, 1997). Adequate plant sanitation and product temperature control as well as maintaining personal hygiene are important in minimising the risk of product contamination.
Some pathogens and spoilage organisms may form attached microbial communities that flourish on the surfaces of water distribution systems (Momba, 1997; September et al., 2006) causing deterioration of the quality of processing water and contamination of the final end product. Formation of these structures (biofilms) is normally a response to unfavourable conditions such as low temperatures and nutrient scarcity. Bacteria in biofilms are embedded in a semipermiable complex formed as a result of increased secretions and deposition of extracellular polymers that promote resistance of th microorganisms to disinfectants such as chlorine and UV irradiation. In water distribution systems biofilms are normally formed as a result of surface attachment after repair and multiplication of sub-lethally injured microorganisms (Momba, 1997). Although chlorine is the conventional chemical sanitizer used in fish processing establishments other disinfectants such as ozone, and hydrogen peroxide may prove more efficient. In addition these two sanitizers are legislated and do not leave toxic by-products (Kim et al., 1999b; Lück and Jager, 1997).
CHAPTER 1 GENERAL INTRODUCTION
1.1 BACKGROUND
1.2 PROBLEM STATEMENT
1.3 JUSTIFICATION OF THE STUDY
1.4 AIMS AND OBJECTIVES
1.5 HYPOTHESES
1.6 ORGANISATION OF THE THESIS
1.7 REFERENCES
CHAPTER 2 LITERATURE REVIEW
2.1 INTRODUCTION
2.2 MARINE FISHING INDUSTRY IN NAMIBIA
2.3 QUALITY AND SAFETY OF SEAFOOD
2.4 VIBRIO SPECIES AS FOOD-BORNE PATHOGENS
2.5 CONTROL OF BACTERIAL CONTAMINATION DURING FISH
PROCESSING
2.7 REFERENCES
CHAPTER 3 SHIKONGO-NAMBABI MNNN, CHIMWAMUROMBE PM and VENTER SN (2010) FACTORS IMPACTING ON THE MICROBIOLOGICAL QUALITY AND SAFETY OF PROCESSED HAKE. African Journal of Biotechnology 9 8405-8411
3.1 ABSTRACT
3.2 LIST OF ABBREVIATIONS
3.3 INTRODUCTION .
3.4 MATERIALS AND METHODS
3.4.1 Sampling
3.4.2 Mesophilic and psychrotrophic plate counts
3.4.3 Sucrose fermenting Vibrio species
3.4.4 Sucrose non-fermenting Vibrio species
3.4.5 Enterobacteriaceae
3.4.6 Pseudomonas, Shewanella putrefaciens and Aeromonas
3.4.7 Statistical analysis
3.5 RESULTS
3.6 DISCUSSION
3.7 CONCLUSION
3.8 ACKNOWLEDGEMENTS
3.9 REFERENCES
CHAPTER 4 SHIKONGO-NAMBABI MNNN, CHIMWAMUROMBE PM and VENTER SN (2010) IDENTIFICATION OF VIBRIO spp. ISOLATES OBTAINED FROM PROCESSED MARINE FISH Proceedings of the National Symposium 15-17 September Safari Hotel Windhoek, Namibia (In print)
4.1 ABSTRACT
4.2 INTRODUCTION
4.3 MATERIALS AND METHODS
4.4 RESULTS
4.5 DISCUSSION
4.6 CONCLUSION
4.7 RECOMMENDATIONS
4.8 ACKNOWLEDGEMENTS
4.9 REFERENCES
CHAPTER 5 SHIKONGO-NAMBABI MNNN, KACHIGUNDA B and VENTER SN (2010) EVALUATION OF OXIDISING DISINFECTANTS TO CONTROL VIBRIO BIOFILMS IN TREATED SEAWATER USED FOR FISH PROCESSING. Water SA 36 215-220
CHAPTER 6 CONCLUSION AND RECOMMENDATIONS
