Masters Degrees (Food Science)
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Browsing Masters Degrees (Food Science) by browse.metadata.advisor "Basson, D. S."
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- ItemThe benefits of the hazard analysis critical control point (HACCP) system in the fishing industry(Stellenbosch : Stellenbosch University, 2000-12) Uys, Rolf (Roelof Christiaan Bosenberg); Basson, D. S.; Britz, T. J.; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.ENGLISH ABSTRACT: International food trade is steadily increasing, as is the global incidence of foodborne diseases. For this reason, governments require that food safety is managed formally and pro-actively within and across the borders of countries. The HACCP system has been proven over the years to be a system, which successfully manages food safety and is fast becoming mandatory in most developed countries. Procedures are also in place to enforce HACCP implementation in South Africa in the near future. The system is preventative in nature and focuses resources on areas, which are critical to food safety, thereby being practical and effective. HACCP has always been and is currently very prominent in the international and local seafood industry. Moreover, South African fish processing companies cannot export their products to most international markets without implementing HACCP. The fish species which are most caught and economically the most valuable in South Africa are the Cape hake (Merluccius capensis and Merluccius paradoxus) and the South African pilchard (Sardinops sagax). This study focussed on applying HACCP principles to these species. HACCP models were developed for a South African pilchard canning operation and a fresh Cape hake processing operation according to the seven principles recommended by the Codex Alimentarius commission. The study showed how the storage of the catch in boat holds was proven to be a critical control point. The hazard was proven to be histamine poisoning due to the fact that boat holds were not cleaned adequately. Histamine-producing bacteria could grow on dirty surfaces and contaminate the catch with the toxin histamine, which could not be destroyed by subsequent canning processes. Viable contact plate counts and histamine-producing bacteria counts were performed. Results showed high counts in both instances, which validates that the point of hold cleaning is a CCP (Critical Control Point). Control measures were implemented in the form of a master cleaning schedule. Viable contact plate counts and histamine producing bacteria counts were repeated after the master cleaning schedule had been implemented. Counts decreased significantly in both instances, which validates the efficacy of the control measures. Ecologically justified, achievable target levels were calculated for viable contact plate counts and histamine-producing bacteria counts, which in future could be used in the HACCP plan of the case study company. The study also showed how a HACCP verification study was conducted on a fresh Cape hake processing operation, in order to illustrate the concept of verification. Microbial growth due to poor temperature control was selected as the hazard. The verification performed was to log times and temperatures during processing, and to ascertain whether temperature control was adequate to prevent the hazard. Logging took place during all stages of processing from catching and holding in the on-board stacker pond, through to selling on a fish market in Vitoria, Spain. Results of the study showed that the fish was reduced to below the critical limit of 3°C within 6 h and that it was kept under the critical limit during all stages of the process. This verifies that the hazard of microbial growth is controlled adequately. This study may be used as a guideline to implement HACCP in a fish processing operation. The hard work, however, lies in customising and streamlining the system for each individual company. In order to achieve this, commitment should be available from top management and the system should be accepted and understood by all employees of the company. HACCP is also dependant on pre-requisite systems such as GMP, which should be in place before the system can work adequately. It is, furthermore, important that HACCP is practiced by all sectors of food processing from farm to fork. The South African fishing industry carries the responsibility of leading the way and showing the rest of the food processing industry how HACCP should be implemented. Being South Africa’s ambassadors in the international food safety arena, it is crucial for the sake of future exports and economic growth that HACCP is implemented and functioning in this area.
- ItemCharacterisation and utilisation of microbes in the production of fish sauce and paste(Stellenbosch : Stellenbosch University, 2000-12) Lubbe, Beatrix; Britz, T. J.; Basson, D. S.; Stellenbosch University. Faculty of AgriSciences . Dept. of Food Science.ENGLISH ABSTRACT: Fermented fish products are popular food products mainly consumed and produced in Southeast Asia. These products are not produced in South Africa, and those available to the public are imported. The main action during the production and fermentation of this sort of product, is that of proteolysis, either by the bacteria or enzymes naturally present in the fish. The prevalent microbes present in six fermented fish samples from Bangkok (Thailand) and seven from Khon Kaen (Thailand), were determined, and using numerical methods, clustered into similarity groups using the calculated dendrogram .distance (Do) technique to determine their relation to reference strains. Forty-seven different bacterial strains were isolated, but no yeasts, moulds or lactic acid bacteria were found. Five Gram-negative, oxidase-positive species, five different Staphylococcus species and nine different endospore-forming species of the genus Bacillus, were isolated and identified using the API systems. The data indicated that members of the genus Bacillus were the prevalent organisms in all the products examined. The isolates were also scanned for general enzyme activity using the API Zym technology, and the production of proteases was investigated using the Standard Methods Caseinate and the Universal Protease Substrate methods. It was found that most of the isolated organisms produced protease, which is of major importance in the production of fermented fish products. Proteolytic cultures from the fermented fish products, as well as lactic acid starters, were used in the production of a fermented fresh water fish product. Production parameters including: glucose, inoculum, moisture content and incubation time, were evaluated in order to select optimum fermentation conditions. Fermentation efficiency was determined by measuring the final pH, titratable acid and the free amino nitrogen content. Optimum efficiency was obtained with 5% (w/w) added glucose at a moisture level of 150 ml water per 100 g fish. A factorial design (3 x 3 x 3) was used to indicate viable trends to facilitate optimisation of the fermentation process. The main effects, two-factor and three-factor interactions were calculated. Optimum trends obtained were a glucose concentration of 5% (wlw) , inoculum concentration of 1x10⁸ kve.ml ̄ ¹, an incubation period of 15 days and temperature of 30°C. Three lactic acid starters (226 - Lactobacillus plantarum, 140 - Lactococcus diacetylactis and 407 - Pediococcus cerevisiae) were selected as they produced some of the best fermentation results and are safe to use in food. It was found that a combination of all three strains (226, 140 and 407) yielded the best results. By using the above parameters, an acceptable product was produced in terms of consistency, colour and aroma. Further studies need to be conducted to optimise the safety of the product as well as the flavour, both chemically and sensorically optimisation of the product.