Masters Degrees (Food Science)

Permanent URI for this collection

Browse

Recent Submissions

Now showing 1 - 5 of 226
  • Item
    The effect of steam pasteurisation and gamma-irradiation on the microbial profile of Aspalathus linearis (Rooibos) tea and the investigation of the native lactic acid bacteria profile
    (Stellenbosch : Stellenbosch University, 2023-12) Groenewald, Jadri; Gouws, Pieter Andries; Kirby-McCullough, B.; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: Due to the increase in popularity of rooibos amongst local as well as international consumers, as reported by the South African Rooibos Council (SARC), rooibos in recognised as an economically valuable crop leading to an increase in commercial farming (Koch et al., 2012, Joubert et al., 2011). The increase in commercial farming requires the establishment of a commercial process that not only ensures consistent quality of the final product but ensures adherence to both local and international regulations regarding the microbiological safety of herbal foodstuffs. Research in needed to not only determine the quality attributes associated with the products unique polyphenolic profile but to determine processing parameters that allow for standardised production processes with measurable quality control points as well as critical control parameters, thus ensuring a consistent quality as well as safe product for the consumer. As such this study aimed to assess the efficacy of the currently employed steam pasteurisation process as well as an alternate cold pasteurisation process, namely gamma irradiation, at reducing the microbial load of the final product. It was found that the steam pasteurisation process ensured a greater than 3 log reduction of total aerobic microorganism density as well as coliform density, however the organisms remained present at a detectable level. However, Salmonella spp. were detected on 3% of the pasteurised rooibos samples thus indicating that the currently employed microbial reduction step, namely steam pasteurisation, is not able to reduce the Salmonella CFU/g to not detected in 25g as required by international food safety microbial guidelines. In comparison gamma irradiation at a dose rate of equal to or above 7.5 kGy is was found to reduce the microbial load of fermented rooibos so as to adhere to both local and international regulations regarding the microbial contamination of herbal foodstuffs. The results indicate that gamma irradiation at a dose rate of 7.5 kGy is a viable option as an alternative to the current industry standard of steam pasteurisation. Furthermore, gamma irradiation was shown to have the ability to reduce the anaerobic endospore former density to undetectable levels, as compared to steam pasteurisation which only achieved a 0.01 log reduction, thus ensuring a safer product for the consumer as compared to a steam pasteurised rooibos product. The second aim of this study was to determine whether dried fermented rooibos could serve as a matrix for the isolation of lactic acid bacteria. The results indicated that fermented rooibos could serve as an isolation matrix for lactic acid bacteria as the following species were isolated though through culture dependent methods; Lactobacillus, Pediococcus, and Weissella. However, it remains important that the microbiome of rooibos tea is explored as a novel niche for the isolation of robust lactobacterial strains that can be applied in the food processing industry.
  • Item
    An evaluation of food safety culture in retail stores in the Western Cape, South Africa
    (Stellenbosch : Stellenbosch University, 2023-03) Becker, Line; Krugel, Maricel; Gouws, Pieter; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: The retail food sector forms one of the most significant sectors within the food industry. The safety of food supplied by retail stores constantly faces concerns and is the topic of food safety culture (FSC) increasingly recognised as a contributory factor to the safety performance of an organisation. The concept behind FSC as a behaviour-based system is not commonly evaluated within standard methods to improve food safety (FS) performance. Food safety culture focuses on the people rather than just the processes, providing background for creating and conserving FS perceptions, mindsets, and beliefs. Incorporating human factors such as leadership, communication, commitment, risk awareness, attitudes, behaviours and FS knowledge to evaluate the culture, has recently been added to FSC studies. These contributory factors analyse and give insight into the culture and help identify areas of concern that need attention to ensure a safe food supply and reduce the associated risks. Food handlers that are not behaving in compliance with standards, not having sufficient knowledge, and lack good leadership qualities within food settings, will result in a poor culture. Contradictory, a positive FSC will regard FS as the number one priority. This research study partnered with one of the five dominant corporations controlling the retail industry in South Africa and aimed to evaluate the FSC within their stores in the Western Cape. A three-phase exploratory research design was used to get a clear view and understanding of the contributing factors of FSC. Three data collection methods were utilised in each phase: survey research, an observational study, and microbiological analysis to enforce method triangulation and develop a multidimensional perspective on the FSC within this retail group (RG). The five components related to FS climate were evaluated through a self-reported questionnaire, and a total of 151 food handlers (seventeen stores) participated. Furthermore, food handlers’ behaviours and the microbiological outcome of the retail stores were evaluated. Phases 2 and 3 were performed in nine stores. This study illustrated that many components contribute towards the FSC of an organisation, and three factors, derived from Bandura’s reciprocal determinism model and known as the ‘person’, ‘behavioural’ and ‘situational’ factors, were used to evaluate the FSC. Ultimately, this approach made it possible to evaluate the organisations’ strengths and weaknesses, specific elements that impact the culture and the overall FSC of the RG, mainly classified as faulty based on the results obtained in phases 1-3. The survey showed that the food handlers achieved an above-average FS knowledge score (62%) and the five climate components received average perception scores between 75-85% - creating a considerably high FS climate perception. The commitment towards FS within stores rewarded the lowest perception score (75%), and the risk awareness factor received the highest score of 85%. However, the FS knowledge achievement and behaviours out of compliance (observed during the observational phase) contradicted the high score obtained for risk awareness. Almost half of the participants had less than seven years of experience (51%) within the food industry, contributing negatively towards the food handlers’ knowledge and attitude. Likely, the FS knowledge and FSC were not accurately reflected by the level of education food handlers previously achieved but could instead be triggered by the training sources related to FS. The observational and microbiological analysis identified the five FS topics classified as areas of concern: food and ingredient storage, proper cleaning practices, personal hygiene of food handlers, safe food handling practices, and the training related to FS. These FS topics identified mainly contradicted the results obtained within the FS knowledge questionnaire. In the end, most participants were not accurately aware of the concept of FSC and the behaviours in compliance with safe food handling. Together with inconsistency observed in food handling practices, the results identified a lack of FS knowledge, leadership, commitment and communication. The lack of knowledge about FS risks associated with poor safe food handling practices illustrated a need among food handlers to receive proper FS training to spend their efforts on these topics and to initiate improvement plans. This research project met the objectives by conducting three-phase exploratory research and method triangulation to evaluate the FSC in stores’ part of the retail group and addressing certain aspects that can affect an organisation’s FSC. Furthermore, recommendations to improve their FSC were discussed, FS gaps were identified, associated risks were explained, and assistance was provided to improve the training the RG supplied. The findings also provided valuable insight to the RG on developing, improving, and maintaining a positive FSC.
  • Item
    Optimising food loss and waste measurement practices in the South African grocery retail sector
    (Stellenbosch : Stellenbosch University, 2023-03) Hobson, Suzaan; De Lange, Willem; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: Food loss and waste (FLW) has economic, environmental, and reputational implications for retailers. According to South Africa's FLW Voluntary Agreement, to move towards achieving Sustainable Development Goal (SDG) 12.3 (reduce FLW by 50% by 2030) the grocery retail sector’s primary response should be to develop a baseline for tonnes of FLW in operations by destination. Without accurate quantification systems in place, the retail sector cannot track progress against targets and identify hotspots. The Voluntary Agreement encourages retailers to use the World Resources Institute’s FLW Accounting and Reporting Standard. It is widely used for quantifying food throughout the supply chain. This research study aimed to determine the appropriateness of the FLW Standard and its complementary reporting template as a tool to accurately quantify FLW for South African retailers. The research procedure involved using data from a major South African retailer to populate the FLW Standard’s reporting template. Qualitative and quantitative FLW secondary data was used for a 3-month trial period across all the retailer’s stores in South Africa. This data was used to identify areas for improvement and to investigate measures that can be taken to reduce FLW in this stage of the food supply chain. It was found that the FLW Standard provides a reliable and consistent methodology for measuring, reporting, and managing FLW. Limitations and challenges were discussed- such as capturing product weight data and streamlining data from contracted waste collectors. The reporting tool was praised for encouraging transparency and guiding the retailer in implementing measurement best practices. Based on the success of the case study it was concluded that the use of this FLW Standard and its reporting template will support South African retailers in their efforts to make progress against the SDG 12.3 target. The study also succeeded in contributing to the knowledge gap pertaining to FLW quantification in the South African retail sector. Several recommendations were made to improve the reporting template for better FLW data optimisation, such as using the results of the reporting template to build a business case for FLW reduction initiatives. Tool plugins linking FLW tonnage to a carbon footprint and other embedded resource statistics are a possible future addition that can be made. It will be beneficial for the retail sector to move towards mandatory FLW reporting; however, retailers should be cognisant that efforts focused on tackling the causes of FLW should be conducted in parallel.
  • Item
    Working towards SDG Target 12.3 baseline values: quantifying food losses in the fruit processing stage of the food supply chain in South Africa
    (Stellenbosch : Stellenbosch University, 2023-03) Linde, Leandri; Sigge, G. O. ; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: The prevalence of food loss and waste in the production of goods for human consumption represents a significant obstacle to the establishment of a sustainable food system. Fruit is a major food commodity that is disproportionately affected by high levels of food loss and waste (FLW) throughout the global food supply chain. In South Africa, 25% of all fruit produced is processed through techniques such as juicing, canning, and drying. These fruit processing activities are known for significant quantities of inedible fruit losses in the form of stems, pips, stones and peels. However, in depth quantification into the edible quantities lost during fruit processing activities in South Africa are limited. A reliable quantification methodology to account for edible fruit losses within the fruit processing stage of the food supply chain in South Africa is important to measure and monitor progress towards the United Nations Sustainable Development Goal Target 12.3. The aim of this study, therefore, was to establish a methodology for determining the magnitude of fruit losses, including the differentiation of edible and inedible losses, within the fruit processing sector of South Africa. The quantification of fruit losses was based on desktop study findings on the quantities and configuration of fruit processed in South Africa, estimates published in scientific literature and databases, and survey responses gathered in the present study. This study found that the total amount of fruit losses generated from the fruit processing stage in South Africa amounts to 44% of the total input weight of fruit sent for processing annually. This 44% loss is further split into 24% edible fruit losses and 20% inedible fruit losses. The findings from the present study can be used by decision makers within government, business and the fruit processing industry to better understand the definitional framework of food losses that are aligned with SDG Target 12.3, and to determine where the food loss hotspots are for further research to design and implement targeted prevention or reutilization strategies for food loss reduction in the fruit processing stage of the South African food supply chain.
  • Item
    The effects of sauerkraut on human health, nutrition, and food security: a review of the literature
    (Stellenbosch : Stellenbosch University, 2023-03) Ngcamu, Sibongile Princess; Sigge, G. O.; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: South Africa has a diversity of native fruits and vegetables, grown for domestic, commercial, and international exports. All fruits and vegetables are beneficial for human health because of the nutritional value they offer. These are antioxidants, polyphenols, and the fibre they contain. When the production, processing and distribution is adequately managed, a population is guaranteed food- nutrition- security. Food must be properly kept and stored, to avoid food waste. Cabbage, as the core focus in this study, evidence shows that huge quantities of this crop go to waste in South Africa, because it is highly perishable. To mitigate such losses, an ancient preservation method is explored in this study, and may enhance the country’s economy. Fermenting cabbage to sauerkraut has beneficial effects on human health, nutrition, and food security. The advantage of fermenting cabbage is that even the smallholder producers can adopt the process, since it can be used even within households and requires no specialised equipment. Moreover, commercially fermenting the cabbage may enhance exports to both the European countries and the United States, who are high consumers of sauerkraut. Fermentation is a food preservation method that makes a high contribution to communities when it comes to enhanced health, whether for children, nursing mothers or the elderly. Sauerkraut was also used to be the main source of Vitamin C for the sailors to prevent Scurvy, a condition responsible for the death of over two million people in the Royal Navy between the 1500’s and mid-1800’s.