In southern Africa, the connections between climate and the water–energy–food nexus are strong. Physical and socioeconomic exposure to climate is high in many areas and in crucial economic sectors. Spatial interdependence is also high, driven, for example, by the regional extent of many climate anomalies and river basins and aquifers that span national boundaries. There is now strong evidence of the effects of individual climate anomalies, but associations between national rainfall and gross domestic product and crop production remain relatively weak. The majority of climate models project decreases in annual precipitation for southern Africa, typically by as much as 20% by the 2080s. Impact models suggest these changes would propagate into reduced water availability and crop yields. Recognition of spatial and sectoral interdependencies should inform policies, institutions and investments for enhancing water, energy and food security. Three key political and economic instruments could be strengthened for this purpose: the Southern African Development Community, the Southern African Power Pool and trade of agricultural products amounting to significant transfers of embedded water. | This work was supported by the following Belmont Forum members: US National Science Foundation (grant number 1342742), UK Natural Environment Research Council (grant number NE/L008785/1) and the South Africa National Research Foundation (grant number 86975), according to each agency’s policies. T.K. and K.L. are funded, through IRI THESys, by the German Excellence Initiative. IFPRI’s contribution is under the CGIAR Research Program on Water, Land and Ecosystems. | http://www.nature.com/nclimate | hb2016 | Geography, Geoinformatics and Meteorology

Notwithstanding the dispersed nature of the water, energy and food (WEF) nexus scholarship in the African continent, its strategic importance to the African agenda has gained widespread attention in research and planning circles. In this regard, the bibliometric science mapping and content analysis of the WEF nexus scientific publication trends, the conceptual, intellectual and social structures, as well as the inherent paradigmatic shifts in the WEF nexus body of knowledge in the African continent have been undertaken, using the nexus body of literature accessed from the Web of Science and Scopus core collection databases. The review results confirmed that, whilst the WEF nexus scholarship has expanded since 2013, there is also evidence of growth in the conceptual, intellectual and social structures of the WEF nexus in the African continent. These shifts have resulted in the emergence of hot topics (subfields) including modelling and optimization, climate variability and change, environmental ecosystem services sustainability, and sustainable development and livelihoods. The review further determined that these structures have evolved along two main perspectives of WEF nexus research development, i.e., the interdisciplinary and transdisciplinary domains. In support of the interpretation of the visual analytics of the intellectual structure and changing patterns of the WEF nexus research, the shifts in positivist, interpretivist and pragmatic paradigmatic perspectives (these are underpinned by the ontology, epistemology, and methodology and methods) are considered when explaining WEF nexus research shifts: (a) From the unconnected silo paradigms that focus on water, energy and food (security concerns) to interconnected (and sometimes interdependent or nested) linkages or systems incorporating environmental, social-economic and political drivers (also viewed as subfields) in a bid to holistically support the Sustainable Development Goals (SDGs) across the African continent; and (b) in the evaluation of the WEF nexus scholarship based on novel analytical approaches. We contend that whilst the theories of science change underpin this apparent expansion, the macro-economic theory will find use in explaining how the WEF nexus research agenda is negotiated and the Integrative Environmental Governance (IEG) is the duly suited governance theory to bridge the inherent disconnect between WEF nexus output and governance processes uncovered in the literature. Overall, operational challenges and opportunities of the WEF nexus abound, transitioning the WEF nexus research to practice in Africa, motivating the need to take advantage of the scholar–practitioner research underpinnings, as contemplated in the transdisciplinary research approach, which is characterised by the dual quest for new knowledge and considerations of use. Yet, there is need for more coordinated and collaborative research to achieve impact and transition from WEF nexus thinking to WEF nexus practice. | The Water Research Commission of South Africa. The APC was funded by the University of KwaZulu-Natal’s Centre for Transformative Agricultural and Food Systems. | https://www.mdpi.com/journal/sustainability | dm2022 | Geography, Geoinformatics and Meteorology | School of Health Systems and Public Health (SHSPH)

Promoting household food security and reducing malnutrition rates of a growing population with the same amount of water is a challenge facing South African nutritionists and agriculturalists alike. Apart from non-food related effects of agriculture in general, the crop and livestock production practices of the South African smallholder farmer may have nutritional implications, primarily when practised on residential land and resulting in home consumption. Yet, few studies have systematically investigated the impact thereof. It appears that crop diversification, gender issues and nutrition education are among the important factors that strengthen the link between agriculture and nutrition. Since food production is the most water-intensive activity in society, nutritional water productivity (i.e. nutrition per volume water) of foods and the nutritional water footprint of diets should be investigated in order to achieve a sustainable solution. This implies that both the demand for a diet consisting predominantly of water-productive plant products, as well as the supply thereof, be addressed.

Dissertation (MSc (Microbiology))--University of Pretoria, 2007. | A total of 94 Salmonella isolates were collected from three catchments areas in Eritrea. These isolates were recovered from clinical and environmental sources. Biochemical tests using gelatin hydrolysis and tartrate utilization test were employed to differentiate between Salmonellasubspecies. All Salmonellaisolates were identified as Salmonellasubspecies I and were then subjected to molecular characterization. Polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP) were employed to identify and establish possible relationships between the clinical isolates and environmental sources. Two sets of oligonucleotide primers specific for genes from S. Typhimurium and S. Enteritidis were used for the PCR reaction. Of the 94 Salmonellaisolates characterized only 6 were S. Typhimurium strains. To type the Salmonellaisolates AFLP was used. Clustering the AFLP patterns using the un-weighed pair-group method using arithmetic means (UPGMA) revealed 15 clusters. Of the 94 Salmonellaisolates collected, 48 (51%) strains were serologically identified. These serotypes include, 21 SalmonellaEmek (43.7%), 19 SalmonellaHeidelberg (39.5%), 7 of the 13, 22, 23; z undetermined serotype (14.5%), and 2 SalmonellaTyphimurium strains (4.1%). The AFLP data in the present study indicated a possible relationship between the clinical isolates and those obtained from environmental sources. | Microbiology and Plant Pathology | unrestricted

Thesis (PhD)--University of Pretoria, 2018. | Diarrheagenic Escherichia coli (DEC) has been implicated in foodborne outbreaks worldwide and additionally associated with childhood stunting in the absence of diarrhoea. DEC are pathogenic E. coli that cause human gut gastrointestinal infections. They are categorized based on how they elicit disease into groups called pathotypes. Infection is extraordinarily common, but the routes of transmission have not been determined. This work categorized into three phases 1, 2 and 3 aimed at characterizing pathogenic E. coli previously isolated from food sources and irrigation water in South Africa. In phase 1, the study characterized 205 E. coli strains previously isolated from producer distributor bulk milk (PDBM)(n=118), irrigation water (n=48), irrigated lettuce (n=29) and street vendor coleslaw (n=10) in South Africa. Enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) were sought. The study used PCR and partial gene sequencing for all 205 strains while 46 out of 205 that showed poor resolution were subsequently characterized using cell adherence (HeLa cells). PCR and partial gene sequencing of aatA and/or aaiC genes confirmed EAEC (2%, 5 out of 205) as the only pathotype. Strains from Genbank showing ?80% nucleotide sequence similarity with those used in this study based on possession of the aaiC gene included 10 clinical and 5 food strains. On the other hand, all strains from GenBank (n=22) showing high nucleotide sequence similarity (?80%) to those from this study based on possession of the aatA gene were clinical. Cluster analysis of sequenced EAEC strains with E. coli strains in GenBank showing ?80% nucleotide sequence similarity based on possession of aaiC and aatA generated distinct clusters of strains separated predominantly based on their source of isolation (food source or human stool). This suggested a potential role of virulence genes in source tracking. EAEC 24%, 11 out of 46 strains (PDBM=15%, irrigation water=7%, irrigated lettuce=2%) was similarly the predominant pathotype followed by strains showing invasiveness to HeLa cells, 4%, 2 out of 46 (PDBM=2%, irrigated lettuce=2%), using cell adherence. All strains that were not characterized based on possession of virulence genes and cell adherence assays were designated as non-DEC. These non-DEC strains were subsequently used as the basis for characterization in phase 2. In phase 2, the study assayed non-DEC strains from environmental sources in South Africa for phenotypes that may be associated with intestinal dysfunction (ID). DEC strains were also used. The strains had previously been isolated from PDBM, irrigated lettuce, street vendor coleslaw and irrigation water. In-vitro assays included; biofilm formation (n=38), extracellular polymeric substance (EPS) formation (n=38), cytotoxic activity (n=10), disruption of tight junctions and induction of Interleukin 8 (IL-8) on polarized T-84 cells (n=20). The number of strains tested for each assay differed, depending on prior molecular and phenotypic characterization that signalled potential pathogenicity. Subsequently, all strains having data points for all analyses were used to compute Principal Component Analysis (PCA) plot curves to infer associations amongst test strains. Biofilm formation varied based on pathotype (DEC and non-DEC) and source of isolation suggesting these two factors influence persistence within a defined environmental niche. Additionally, DEC isolated from irrigated lettuce had significantly higher (p?0.05) biofilm formation in both media compared to all strains including DEC standard controls suggesting irrigated lettuce as a potential source of persistent pathogenic strains. All strains were able to form EPS suggesting ability to form mature biofilms. Of the (60%, 6 out of 10) strains showing cytotoxic activity, most (83%, 5 out of 6 strains) were non-DEC isolated from food sources. Mean percentage reduction in initial TER (a measure of intestinal disruption) in all test strains, was comparable (53.5 to 73.8%) to that observed in the standard DEC. Additionally, IL-8 induction from strains isolated from PDBM (139pg/mL), irrigation water (231.93pg/mL) and irrigated lettuce (152.98pg/mL) was significantly higher (p?0.05) than in the commensal strain aafa. PCA categorized strains based on sources of isolation and showed potential for use in source tracking. This study shows that non-DEC strains along the food chain possess characteristics that may lead to ID. However further investigations with a larger collection of strains may provide a clearer link to these observations. | Food Science | PhD

We have previously shown that diarrheagenic Escherichia coli (DEC) and non-DEC are prevalent in food sources and irrigation water in South Africa. Recent data suggest that an increased relative abundance of faecal Enterobacteriaceae is associated with poorer health outcomes among children in developing countries. Thus, exposure to non-DEC from environmental sources may incur adverse effects, although the mechanisms underlying these effects remain obscure. To further elucidate this phenomenon, we assayed non-DEC strains from environmental sources in South Africa for phenotypes that may be associated with intestinal dysfunction (ID). DEC strains were also used. The strains had previously been isolated from Producer Distributor Bulk Milk (PDBM), irrigated lettuce, street vendor coleslaw and irrigation water. In-vitro assays identified; biofilm formation (n = 38), extracellular polymeric substance (EPS) formation (n = 38), cytotoxic activity (n = 10), disruption of tight junctions and induction of Interleukin 8 (IL-8) on polarized T-84 cells (n = 20). The number of strains tested for each assay differed, depending on prior molecular and phenotypic characterization that signalled potential pathogenicity in-vitro. Subsequently, all strains having data points for all analyses were used to compute Principal Component Analysis (PCA) plot curves to infer potential associations amongst test strains and a standard DEC pathogenic strain (042). Biofilm formation on glass coverslips after strains were grown in nutrient-rich media (LB and DMEM-F12 + 0.5% D-Mannose) at 37 °C varied based on pathotype (DEC and non-DEC) and source of isolation (food, irrigation water, clinical) suggesting that pathotype and source isolation influence persistence within a defined environmental niche. Additionally, DEC isolated from irrigated lettuce had a significantly higher (p ≤ 0.05) propensity for biofilm formation in both media compared to all strains including DEC standard controls. This suggested the propensity for irrigated lettuce as a potential source of persistent pathogenic strains. Furthermore, all strains were able to form EPS suggesting the ability to form mature biofilms under conditions relevant for food processing (20–25 °C). Of the (60%, 6 out of 10) strains that showed cytotoxic activity, most (83%, 5 out of 6 strains) were non-DEC isolated from food sources many of which are consumed with minimal processing. Mean percentage reduction in initial TEER (a measure of intestinal disruption), did not significantly differ (p = 0.05) in all test strains from that observed in the standard DEC. Additionally, IL-8 induction from strains isolated from PDBM (139 pg/mL), irrigation water (231.93 pg/mL) and irrigated lettuce (152.98 pg/mL) was significantly higher (p ≤ 0.05) than in the commensal strain aafa. PCA categorized strains based on sources of isolation showed potential for use in source tracking especially when comparing many strains from various environmental sources. We show that non-DEC strains along the food chain possess characteristics that may lead to ID. Further investigations using a larger collection of strains may provide a clearer link to these reported observations that could be associated with the high diarrheal disease burden within the country, especially among infants. | The Department of Research and Innovation, University of Pretoria for a post-graduate travel bursary to Matthew Aijuka to travel to James P. Nataro's laboratory at The University of Virginia. Work in the Nataro lab was supported by US National Institutes of Health grant AI-33096 to JPN. | http://www.elsevier.com/locate/foodcont | 2020-08-01 | hj2019 | Food Science

Access to clean water, reliable energy services and adequate food supply are basic needs for life and contribute to the reduction of national and global levels of human poverty and forced migration. This study concentrated on reviewing progress made in understanding the relationship between the Water-Energy-Food (WEF) nexus and climate change adaptation, using Africa as a case study. The method used to achieve this objective was the bibliometric analysis, covering the period from 1980–2021. Data used for this study were acquired from theWeb of Science (WoS) and Scopus databases. Initially, 95 documents were retrieved from theWoS and Scopus core collection databases, but 30 duplicates were removed, and 65 documents were used. The outputs were further analysed using the bibliometric R package and VOS viewer. Analysis of the top 100 keywords in the 65 publications that link WEF nexus with climate change adaptation for Africa showed that 46 keywords fall under the application of WEF nexus, 31 keywords under the implementation of WEF nexus and 23 keywords under the implication of WEF nexus. Researchers from countries around the world have published the WEF nexus work undertaken on the African continent. Countries with the highest number of publications were South Africa, the United Kingdom, the United States of America, Germany, Kenya and Zimbabwe. Thematic analysis was used to explore the conceptual structure of WEF publications, and it produced four themes: (i) well-established concepts appropriate for structuring the conceptual framework of the field of WEF nexus in Africa; (ii) strongly developed concepts but still marginal for the field of WEF nexus in Africa; (iii) not fully developed or marginally interesting concepts for the field of WEF nexus in Africa, and (iv) significant cross-cutting concepts in the field of WEF nexus in Africa in relation to climate change adaptation. This study contributes to the growing body of literature on the WEF nexus by pointing out dominant themes from those that are still emerging in the scholarly work done in Africa. | The Water Research Commission in South Africa. | https://www.mdpi.com/journal/sustainability | am2023 | Geography, Geoinformatics and Meteorology

Dissertation (MSc)--University of Pretoria, 2019. | As mining and industry continue to impact agricultural lands and waterways, and as competition for access to fresh water increases, the agricultural industry must adapt to grow crops in increasingly polluted lands using ever more contaminated water sources. As a result, the likelihood that crops grown under such conditions could pose a food safety risk is set to rise. This research assesses the extent to which potentially hazardous trace elements, As and Pb, present in irrigation water at concentrations deemed acceptable by the Irrigation Water Quality Guidelines, impact the food (and feed) safety of crops. Four crops are investigated under two glasshouse trials. The first assesses foliar absorption of As and Pb under irrigation to the aboveground biomass and the second assesses root uptake of As and Pb via the effects of medium- to long-term irrigation programs. Results indicate that under such trace element loaded conditions, some crop parts exceed food (or feed) safety thresholds, with concentrations ranging from 0.01 mg.kg-1 to 33.38 mg.kg-1 As, and 0.01 mg.kg-1 to 62.41 mg.kg-1 Pb, on a dry mass basis. Leafy vegetables present the highest food safety risk. Therefore, if international food safety standards for fresh produce are to be adhered to, the Irrigation Water Quality Guidelines for As and Pb should be critically reviewed so as to negate all possible future contamination of fresh produce as a result of irrigation inputs. A food (and feed) safety consequence matrix is proposed as a means of modelling the effect of irrigating according to the Irrigation Water Quality Guidelines on food (and feed) safety. | Plant Production and Soil Science | MSc | Unrestricted

Mini Dissertation (MSc)--University of Pretoria, 2012. | Most agricultural water sources are often considered contaminated, due to poorly maintained sanitation systems, polluted river streams and other water catchment areas. Agricultural water used for irrigation and reconstitution of pesticides is suspected to play a direct or indirect role in the transmission of human pathogens to fresh produce. The contamination of fresh table grapes during pesticide spraying can therefore be seen as a potential risk factor. This study focuses on identifying possible sources and levels of bacterial contamination in a river, holding dam and tank in table grape production areas. In addition, the ability of selected pathogens to attach and survive on table grape surfaces was studied using transmission electron microscopy. Water sources sampled in this study were found to be microbiologically contaminated. Microbial populations varied with season, sampling period within a season and water treatment conditions. No human pathogens were detected under natural field conditions on crops irrigated with contaminated water used for reconstituting agricultural pesticides. This study further showed a wide range of pesticide products that permitted survival and multiplication of most of the tested foodborne pathogens i.e. Escherichia coli 157:H7, Listeria monocytogenes, Salmonella enterica subsp. enterica serovar Typhimurium and Staphylococcus aureus. This information provides insight into the potential risk that may be associated with table grapes due to the use of contaminated water. These findings highlight the importance of considering pesticides used, water quality and spray schedules prior to application. Detailed risk assessment studies on the potential of contaminated irrigation water and the actual link with foodborne disease outbreaks have not been investigated and should in future be determined as well as intervention strategies. | Microbiology and Plant Pathology | MSc | Unrestricted

The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format. | 1. The consumption of lucerne hay and water by merino sheep has been recorded in two separate but identically concluded experiments under the following conditions: (i) Both food and water given ad lib. (ii) Water restricted to 2 litres, food ad lib. (iii) Food restricted to 0.6 Kg. water ad lib. 2. A highly significant positive correlation was found between the amounts of hay and water consumed when both were offered ad lib. 3. A highly significant positive correlation was also found between the amount of water consumed and the maximum atmospheric temperature for the day. This coefficient was enhanced by feeding a fixed amount of hay in the first experiment but not in the second. 4 . No direct correlation could be shown between the hay consumption and atmospheric temperature when water supply was unrestricted. In the first experiment a highly significant negative correlation was found between these two factors when a fixed amount of water was given, but this could not be confirmed in the second experiment. 5. Urine was collected from representative animals from each group. It was found that the animals on a restricted water supply maintained a low water to food ratio by passing small amounts of highly concentrated urine (urea up to 8.1 gm. per 100 c.c.). Marked variations were found between individual sheep receiving both hay and water ad lib. in respect of volume and concentration of urine.