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Access status: Open Access ,
Microbiota and associated chemical compounds in South African craft ales
(Central University of technology, 2025) Mogotsi, Lerato Bonolo
Craft beer is typically brewed in smaller batches compared to industrial breweries. Several factors can influence the flavour, quality, and safety throughout the craft beer brewing process, including raw materials, fermentation conditions, and the interactions between the chemical composition and microbial communities. Limited research has been undertaken on the integration of microbial and chemical profiles of craft beers. Therefore, this study aimed to profile the microbial and chemical compositions of South African craft ale beers, to evaluate their safety in relation to the detected microbial and chemical compositions, including the level of mycotoxins, and to explore correlations between the microbiota and the detected compounds. A total of 30 beers (in triplicate) of different styles were purchased from 30 commercial craft breweries and tested for mycotoxin levels using ultra-performance liquid chromatography–electrospray ionisation–tandem mass spectrometry (UPLC-ESI-MS/MS). The most prevalent mycotoxin was deoxynivalenol (DON), which was detected in 10% of the beer samples. The highest concentration of DON (22 μg/L and 41.49 μg/L) was detected in India Pale Ale (IPA) and Stout, while fumonisin FB₁ and FB₂ (0.37 μg/L and 0.16 μg/L) were detected in IPA and Pale Ale, respectively. Nivalenol (NIV) was present in trace amounts (0.13 μg/L) in one IPA sample. The presence of these mycotoxins indicated the need for quality assurance of raw materials used in craft beer production and quality control. Microbial profiling showed total viable microorganisms present up to 1.63 × 10⁵ CFU/mL, yeast was detected in more than 50% of the beer samples, not unexpected since most breweries do not filter or pasteurise their final product. Moulds were present in product from 17% of breweries, and 60% of the breweries presented with lactic acid bacterial (LAB) contamination. Common foodborne pathogens Escherichia coli and Salmonella spp were not detected. Pale Ales from one brewery presented co-occurrence of LAB and Staphylococcus aureus, indicative of post-fermentation contamination. Next-generation sequencing results showed that Acetobacter and Levilactobacillus spp. dominated bacterial communities, while the fungal community was dominated by Saccharomyces cerevisiae, although other non-Saccharomyces genera, including Cladosporium, Vishniacozyma, and Penicillium spp. were also present. Chemical profiling revealed several flavour-active compounds, including isoamyl alcohol (178.9 mg/L), 4-vinylguaiacol (10 mg/L), isoamyl acetate, and vanillic acid (76.7 mg/L), present in concentrations well above sensory thresholds in beer styles in which these compounds are not expected or preferred. The sugar and sugar alcohols varied widely in both type and concentrations. Fructose (107.4 mg/L), xylose (60.6 mg/L), and xylitol (185.4 mg/L) were among the most dominant. A strong positive correlation between higher alcohols, as well as a negative correlation between certain sugars (e.g., maltose, trehalose) and flavour-active compounds was also revealed. This research provides insights into the microbial and chemical profiles of sampled South African craft ales. While these beers may be microbiologically safe and favourably complex, some of the beer samples remain susceptible to post-fermentation contamination and subtle chemical variability. The findings highlight the interconnected role of microorganisms in shaping beer flavour and stability, and they emphasise the importance of maintaining consistent quality in the craft brewery environment. This study establishes valuable baseline data to enhance product safety, sensory consistency, and meet regulatory standards of the rapidly growing craft beer industry.
Access status: Open Access ,
Efficacy of Melaleuca alternifolia and Pelargonium graveolens against Staphylococcus aureus and Staphylococcus epidermidis associated with knee implants
(Central University of technology, 2025) Mbanjwa, Ntombokhanyo
Knee replacement surgery is experiencing a surge in demand worldwide; however, knee infections represent a substantial public health threat, particularly for underserved communities. While knee implantology was innovated to restore functionality to damaged knees, the risk of infections due to bacterial colonisation around the implant remains a serious concern. The overuse of antibiotics not only jeopardises patient health but also escalates healthcare costs. Although prophylactic antibiotic regimens are employed to mitigate infection risks, the emergence of antibiotic resistance due to excessive utilisation has complicated this approach. In this context, essential oils emerge as a promising solution to combat these challenges. Essential oils, known for their natural origins, serve as potent antibacterial agents due to their mechanisms of action, which include disrupting cell walls, damaging cytoplasmic membranes, and causing cytoplasmic coagulation. This study specifically investigates the Essential oils' effectiveness in combatting bacteria associated with knee implants. The research examines the bactericidal properties of Melaleuca alternifolia (tea tree essential oil) and Pelargonium graveolens (geranium essential oil) essential oils against the antibiotic-resistant strains Staphylococcus epidermidis and Staphylococcus aureus. The findings suggest that both Melaleuca alternifolia and Pelargonium graveolens essential oils effectively inhibit bacterial growth linked to knee implants, thereby potentially reducing the necessity for knee implant revisions. The essential oils' chemical constituents were examined utilising gas chromatography- mass spectrometry (GC-MS).Terpinen-4-ol was discovered to be a key component of Melaleuca alternifolia essential oil, including α-pinene, γ-terpinene, limonene, and cymene, which are associated with antibacterial and anti-inflammatory properties. Pelargonium graveolens essential oil consists of citronellol and geraniol as major components that contribute to cell wall disruption, loss of cellular contents, and overall bacterial deformation. The research employed bioassay methods to evaluate the antibacterial effects of Melaleuca alternifolia and Pelargonium graveolens essential oils against S. aureus (ATCC 25923) and S. epidermidis (ATCC 12228). Both Melaleuca alternifolia and Pelargonium graveolens essential oils demonstrated significant inhibitory effects on the growth of S. aureus and S.epidermidis. To ascertain the concentration at which these essential oils can inhibit microbial growth, the minimum inhibitory concentration (MIC) method was utilised. Additionally, the study sought to examine the structural transformations induced by essential oils in microorganisms, employing scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The SEM results revealed observable morphological changes, including slight roughness (R) of the cell surfaces, loss cellular content (LCC), and damage to the cell walls (DCW). The TEM results revealed drastic alterations in the cellular structure of S. aureus and S. epidermidis following exposure to Melaleuca alternifolia and Pelargonium graveolens essential oils. Notable changes included damaged cell walls, the formation of holes, and the depletion of cellular contents, ultimately resulting in cell death. This research holds significant implications for the use of natural products like essential oils as potential alternative bacteriostatic agents. During microbial assessments, it was observed that Melaleuca alternifolia and Pelargonium graveolens essential oils compromised the cell membranes of S. aureus and S. epidermidis, leading to cell death. Consequently, this indicates that both essential oils can effectively target multiple bacterial sites, particularly the plasma membrane and cytoplasm. Moreover, the study highlights some advantages of using natural products such as Melaleuca alternifolia and Pelargonium graveolens essential oils, including the need for the healthcare sector to reduce reliance on antibiotics and consider essential oils as viable alternatives in the fight against microorganisms responsible for knee infections, ultimately decreasing the need for revision surgeries. However, despite the promising nature of essential oils as alternatives to antibiotics, further research is imperative. The impact of essential oils on health and integrity of knee implants, the optimal concentrations that ensure bacterial eradication without harming human cells, and the duration of essential oil adherence to implants remain areas requiring additional exploration, as well as investigating the biofilm formation of bacterial strains on the experimental knee implant.
Access status: Open Access ,
Use of artificial intelligence for predictive maintenance of electric trains in South Africa
(Central University of Technology, 2026) Mavhungu, Sonia Mathalise
Railway transportation plays a critical role in urban mobility and economic development, serving as a primary mode of passenger movement for millions of commuters across South Africa. Despite its strategic importance, the South African rail sector continue to face persistent operational challenges as result of ageing infrastructure, progressive rolling stock degradation, and maintenance regimes that remain largely reactive or time-based. These conventional maintenance regime approaches are not favourable when considering the demands of modern rail operations, as they fail to anticipate subsystem failures before they escalate into costly service disruptions. The inability to detect early fault conditions in critical electrical and mechanical systems has contributed to increased unscheduled downtime, high maintenance costs, and compromised passenger safety, which are challenges that have been witnessed within many railway operational environments. To address these challenges, this study investigated the application of Artificial Intelligence and Machine Learning to develop and implement a predictive maintenance model for electric trains (ET), using a fleet of passenger rolling stock classified as electric multiple units (EMU), operated by the Passenger Rail Agency South Africa as a case study. Operational data was collected from the fleet operator, and a quantitative, simulation-based methodology was followed to evaluate a machine learning predictive maintenance model. The operational data covering a period of two (2) years (2023 – 2024) was collected across three critical subsystems, the pantograph, traction motor, and auxiliary converter unit, monitoring parameters including line voltage, current, temperature, airflow, vibration, and arc frequency. Two supervised machine learning algorithms, Logistic Regression and Random Forest, were trained and evaluated using this dataset. The Random Forest model achieved superior predictive performance, with 93% accuracy, 0.91 precision, 0.88 recall, and an F1-score of 0.89. These results verify the model’s ability to effectively distinguish between normal and early fault modes with high accuracy of detection, which is crucial for safety of railway applications. Furthermore, an analysis in this study revealed that trends in the frequency of high voltage arcs, line voltage deviation and temperature rise in traction motors were discovered to occur prior to recorded fault events. This demonstrated that features derived from these data can be investigated efficiently as an information rich multi-parametric supply for proactive predictive diagnostics. This study has also demonstrated that AI-based Predictive Maintenance can materially improve rail operational efficiency through condition-based intervention, reducing unscheduled downtime. The research adds to the new field of intelligent railway asset management by simulating the integration of AI in a South African passenger rail environment. It provides a methodological framework to shift maintenance from a reactive or time-based approach to a proactive and data centric strategy. Future work is suggested to further develop this work by deploying different methodologies with more sophisticated deep learning architectures for more objects at the same time.
Access status: Open Access ,
Albumin-coated cadmium oxide nanoparticles: synthesis, characterization, and In Vitro and In Vivo evaluation of their biological activity in triple-negative breast cancer
(Central University of Technology, 2026-06) Lefojane, Relebohile Patricia
Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype characterised by the absence of oestrogen, progesterone, and HER2 receptors, limiting the effectiveness of targeted therapies. Conventional chemotherapy remains non-selective and is associated with systemic toxicity and poor bioavailability. This study investigated the synthesis, characterisation, and anti-TNBC therapeutic potential of albumin-coated chemically synthesised cadmium oxide nanoparticles (A-Chem CdO NPs) as a potential nanotherapeutic strategy. Cadmium oxide nanoparticles were synthesised using green, chemical, and albumin-assisted chemical methods, and characterised using UV-Visible spectroscopy, FTIR, XPS, and TEM analyses. In vitro cytotoxicity was evaluated using the MTT assay, while in vivo therapeutic efficacy and systemic toxicity were assessed in a BALB/c mouse model using clinical observations, body mass changes, tumour inhibition rate (TIR), and histomorphological analysis. Chemically synthesised Cadmium Oxide Nanoparticles (Chem CdO NPs) demonstrated the highest in vitro potency and were subsequently functionalised with albumin to improve stability and biocompatibility. Albumin coating reduced the potency in MDA-MB-231 cells, whiththe IC50 increasing from 3.33 μg/mL to 11.32 μg/mL, whereas Doxorubicin (the standard drug) exhibited the greatest potency with an IC50 of 0.34 μg/mL and the highest selectivity index. In vivo, A-Chem CdO NPs induced delayed and milder clinical toxicity compared with Doxorubicin. Although body mass loss was comparable between treatments, Doxorubicin achieved superior tumour inhibition (50–55%), while A-Chem CdO NPs demonstrated moderate antitumour activity (30–35%). Histomorphological analysis revealed tumour necrosis and chromatin condensation in A-Chem CdO NP-treated tissues, indicating moderate tumour regression, with minimal evidence of off-target organ toxicity. Overall, the findings demonstrate that albumin functionalisation altered the biological behaviour of CdO nanoparticles, reducing acute cytotoxicity while maintaining moderate in vivo antitumour efficacy. These results highlight the complexity of nanoparticle therapeutic performance and support further optimisation of albumin-coated CdO nanoparticle systems for TNBC treatment.
Access status: Open Access ,
Machine learning as a tool to forecast the power quality of a wind energy power plant
(Central University of Technology, 2026) Cindi, Mbuyiselwa Lawrence
The large-scale integration of renewable energy sources, particularly wind power, into national grids introduces non-linear and intermittent behaviour that challenges the maintenance of acceptable power quality (PQ). In South Africa, these challenges must be managed within the limits and measurement requirements of NRS 048-2 and related IEC standards at the point of common coupling (PCC). This dissertation investigates how effectively machine learning (ML) models can forecast key PQ parameters at a utility-scale South African wind power plant, and how these forecasts perform when judged not only by conventional regression accuracy but also by compliance-oriented metrics aligned with NRS 048-2 (Missed Violation Rate, MVR, and False Alarm Rate, FAR). Using 10-minute operational SCADA data from the wind-farm PCC, a six-phase, leakage-aware analytical workflow is implemented in JMP Pro 18. The pipeline covers standards-aligned preprocessing, domain-informed feature engineering, chronological train/validation/test splits, and multi-model benchmarking. Four model families are compared: Boosted Trees (BT), Support Vector Machines (SVM), a feed-forward Neural Network (NN), and a SARIMAX baseline. Forecasts are evaluated using RMSE, MAE, MAPE, R² and compliance metrics (FAR, MVR), including a ±5 % sensitivity analysis around key NRS 048-2 limits. Results show that non-linear models are essential for PQ forecasting in this wind-integrated grid. BT consistently delivers the best or near-best performance for Voltage Unbalance, Frequency, long-term flicker (P_lt), and V_RMS (p.u.), achieving high R² (often > 0.95) and low MVR (≈ 5 % for Unbalance, ≈ 0–5 % for P_lt) with FAR typically below 1 %. SVM is particularly strong for V_THD and competitive for P_lt, while the NN performs best on short-term flicker (P_st) in terms of regression accuracy but exhibits higher MVR. SARIMAX underperforms on non-linear and volatile parameters, confirming the limits of purely linear approaches. The study provides the first detailed, NRS 048-2-aligned PQ forecasting case study on a South African wind plant, demonstrates a reproducible, standards-aware modelling pipeline, and shows how FAR/MVR-based evaluation can translate ML forecasts into actionable early-warning tools for grid operators, supporting proactive PQ management in renewable-rich networks.
Access status: Open Access ,
The impact of financial accountability on good governance and service delivery efficiency in selected provincial departments and municipalities in the Northern Cape Province
(Central University of technology, 2026-01) Motsumi, Onkabetse Levy
Accountability (including financial accountability), good governance, and the delivery of effective services are constitutional priorities of South Africa's democratic system. Section 195(1) of the Constitution of the Republic of South Africa, 1996 (hereinafter referred to as the Constitution), states that accountability, including financial accountability, is essential, and that good governance and service delivery should be institutionalised across the three spheres of government. The Public Finance Management Act (Act 1 of 1999) (hereinafter referred to as the PFMA) and the Local Government, Municipal Finance Management Act (Act 56 of 2003) (hereinafter referred to as the MFMA) establish the legislative frameworks for financial management in the public sector. Despite the requirements outlined in Section 195 of the Constitution to deliver services effectively, efficiently, economically and accountably, the ongoing adverse audit outcomes of some provincial departments and most municipalities, including those of the Northern Cape Provincial Government (NCPG), raised questions about the effectiveness of current financial accountability, good governance, and service delivery approaches. By focusing on a few selected provincial departments and local municipalities within the NCP, the researcher projected a comprehensive and holistic picture of the state of financial accountability in the NCP. Thus, the study aimed to contribute theoretically and empirically to the body of knowledge about the relationship between financial accountability, good governance, and service delivery efficiency in selected provincial departments and local municipalities in the NCP. To enhance an understanding on the details of financial accountability, good governance and public service delivery efficiency, the principal-agent theory, public-service dominant logic and new public management theory guided the study on public service delivery and management. The study employed a quantitative research approach and a cross-sectional survey research design to investigate the impact of financial accountability on good governance and service delivery efficiency in selected provincial departments and municipalities in the NCP. The study examined several variables related to financial accountability, good governance and service delivery efficiency, including legislative provisions, public expenditure, oversight bodies, principles of good governance, public service delivery, financial performance outcomes, supply chain management (SCM), financial controls, capacity of staff complements and stability in senior positions. A structured questionnaire was administered to 150 public officials in the selected provincial departments and to 79 municipal officials in the selected local municipalities. This study revealed that a lack of financial accountability frequently led to instances of financial misconduct and the disregard of important legislative frameworks, such as the PFMA, MFMA, and SCM regulations. The empirical phase of study employed both the descriptive and inferential statistical analyses. The empirical study revealed that the largest proportion of respondents from the selected provincial departments and municipalities agreed that poor financial accountability influenced poor financial performance. A significant proportion of respondents agreed that financial accountability has a positive influence on good governance and the efficiency of public service delivery. The hypotheses were tested through Spearman inferential statistical methods and consequently, it was found out that the alternative hypotheses H1a1 to H5a1 were accepted. The study proposed a framework to promote financial accountability, good governance and public service delivery efficiency in the selected provincial departments and municipalities in the NCP.
Access status: Open Access ,
The effect of supplementation of plant and animal-derived dietary oils in pre- and post-parturition Döhne merino ewes on the growth performance of the lambs
(Central University of technology, 2024-06) Sedupane, Tebogo
The objective of this study was to investigate the effect of dietary supplementation of sunflower oil, olive oil, fish oil, and palm oil to pre- and post-parturition Döhne Merino ewes on lamb growth performance. Birth weight, post-natal growth rate, and weaning weight of lambs suckling on supplemented ewes were compared. Fifty South African Döhne Merino ewes, 2–4 years old (second parity), weighing 46–55 kg, with a mean body condition score (BCS) of 3.5 ± 0.4, were randomly divided into groups of 10 animals each. Each group (n = 10 per group) received a daily dose of 30 ml of either sunflower, olive, fish, or palm oil, while the control group received no oil. The study was conducted over a period of 210 days (i.e., 7 months). Oestrus was synchronised through the use of controlled internal drug release (CIDR) devices inserted intravaginally for a period of 15 days. Oestrus synchronisation and oil supplementation commenced simultaneously. At CIDR withdrawal, ewes were injected intramuscularly with 200 IU Pregnant Mare Serum Gonadotrophin (PMSG). Fixed-time laparoscopic artificial insemination (LAI) was performed with diluted Döhne Merino semen 48 hours following CIDR removal. Two weeks after LAI, follow-up Döhne Merino rams were introduced to all 50 ewes for 2 weeks to mate ewes that exhibited any signs of oestrus, as this is standard procedure of the experimental farm, and it was also importatnt that all selected ewes for the experiment conceive, although not part of the objectives of the present research. The production parameters were expressed as an average per group. The mean conception rate and lambing rate of ewes across all groups were 88%. The olive oil treatment recorded the highest conception rate and lambing rate (100% for both), but did not differ significantly (P> 0.05) from other groups. followed by sunflower oil (90%), fish oil (90%), palm oil (70%); the control group had rates of 90%. post-hoc test using Tukey’s HSD to identify significant differences between treatment groups at specific time points at a 95% confidence interval. The IBM Statistical Package for the Social Sciences (SPSS) 27 software programme was utilised. The shortest gestation length of 150 days was recorded for the control group. The gestation lengths of the sunflower oil, olive oil, fish oil, and palm oil groups were 153, 156, 155, and 156 days, respectively, with no significant differences (P > 0.05) between any groups. The birth weights of female lambs from the control, sunflower oil, olive oil, fish oil, and palm oil groups were 5.41 ± 0.87 kg, 5.70 ± 0.61 kg, 5.8 ± 0.70 kg, 5.8 ± 0.74 kg, and 4.9 ± 0.50 kg, respectively. The birth weights of male lambs from the control, sunflower oil, olive oil, fish oil, and palm oil groups were 5.6 ± 1.19 kg, 4.85 ± 0.70 kg, 5.6 ± 0.84 kg, 5.5 ± 0.49 kg, and 5.4 ± 0.33 kg, respectively. The results indicate no significant difference (P > 0.05) between different treatment groups for birth weights for both male and female lambs. There was improvement or significance (P>0.05) on percentage increment in weight over time in weeks 5,9 and 11. There was significant difference experienced in ADG of lambs among groups in weeks 5,6,10,11 and 13. There was no significant difference (P > 0.05) observed in the final body weight at weaning for both males from the control, sunflower oil, olive oil, fish oil, and palm oil groups (28.8 ± 4.93 kg, 25.5 ± 8.13 kg, 29.0 ± 4.88 kg, 30.2 ± 4.59 kg, and 28.8 ± 5.03, respectively) and females from the control, sunflower oil, olive oil, fish oil, and palm oil groups (28.5 ± 4.58 kg, 28.3 ± 3.81 kg, 25.8 ± 6.93 kg, 28.9 ± 4.51 kg, and 27.6 ± 2.46 kg, respectively) for the lambs of ewes supplemented with different experimental dietary oils. There was difference in the effect of plant and animal-derived dietary oils – namely sunflower oil, olive oil, fish oil, and palm oil – on the percentage increment in weight over time and ADG of lambs among groups. The growth performance of the lambs was similar to the control group. It can thus be concluded that, in this study, diets enriched with plant and animal-derived dietary oils pre- and post-mating had an effect on growth performance in Döhne Merino sheep.
Access status: Open Access ,
Enumeration of phyllo-epiphytic and endophytic pathogens on leafy greens from farms and retails as affected by production parameters in the Free State, South Africa.
(Central University of technology, 2025-06) Mohapi, Dineo Attela
Leafy vegetables are a highly variable group of perishable foods that broadly can be defined as vegetables grown for their edible leaves. This study was conducted to investigate the production parameters at the farms and how they influences the end product. The study characterises opportunistic pathogens from various farms and retails and identify the aetiology and how these organisms affect human health and also emphasise the significance of sources that are regarded as microbial hazards or act as resevoirs for pathogenic organisms. Considering one health perspective it is also imperative to pay more attention to the presence of zoonotic pathogens that are resistance to certain antbiotics as it is a public health threat and a challenge that need to be highlighted due to high level of infectious illness caused by zoonotic and opportunistic pathogens. Since various agronomic activities leads to contamination of leafy greens in various stages of minimal processing including distribution, it is thus crucial to address such concerns at small-scale farms to mitigate cross-contaminate to the retails and provide an insight on hygiene and sanitation in both spheres. Minimal process includes many stages which introduces the disruption of tissue including cell integrity resulting in product harbouring of opportunistic pathogens. Spinach (Spinacia oleracea L.) and cabbage (Brassica oleracea var. capitata L.) are considered staple food in South Africa and are consumed daily, they were chosen due to their minimal processing in production, demand, purchase and their difference compared to intact vegetables regarding their physiology, processing, handling including storage. The study profiles and characterise opportunistic and zoonotic pathogens from both regimens due to processing parameters, hygiene practises and possible succession of pathogens form one niche to the other. The first survey was on the enumeration of microbiota on spinach and cabbage isolates from various farms including their storage crates. Secondly, the objective was to enumerate microbiota from spinach and cabbage from retails and further investigate the extent of these pathogens, the succession at the retail level, observe the proliferation of pathogens introduced along the way due to amplification. Fresh leafy spinach, crates and cabbage samples were analysed for each of the following microorganisms: total aerobic mesophilic bacteria, total coliforms, coagulase-positive Staphylococci, Listeria and Bacillus and further identification of isolates was done by utilisng Analytic Profile Index. Lastly, conduct antimicrobial susceptibility profile of identified opportunistics bacteria from farms and retails, the isolates were evaluated utilising Kirby-Bauer disk diffusion method against nine antibiotics from nine categories: penicillin (P; 10_μg), ampicillin (AMP; 10_μg), gentamicin (CN; 10_μg), ceftazidime (CAZ; 30_μg), chloramphenicol (C; 30_ μg), tetracycline (TE; 30_μg), vancomycin (VA; 30_μg), erythromycin (E; 15_ μg) and ciprofloxacin (CIP; 5_ μg). In this study, three farms had the highest number of opportunistic pathogens identified for cabbage with the least number of pathogens observed in the other two farms. With regards to spinach, two farms had the highest number of identified pathogens including Proteus mirabilis, Escherichia coli, Staphylococcus aureus, Serratia species and Listeria species and the lowest number was observed in the other two farms. Concerning spinach crates, two farms had the highest number of pathogens identified and the least numbers were observed in the other two farms. This indicate contamination mostly from livestock manure utilised on the crops including insufficient hygiene from workplace. Secondly, three retails had the highest number of pathogens identified for cabbage compared to the other two retails. With regard to spinach, three retails had the highest number of identified pathogens including Bacillus spp., Enterobacter cloacae, Listeria ivanovii and Listeria monocytogenes species compared to the other two retails. The study also highlights additional bacterial species enumerated from both commodities in two different environments. The additional species characterized are a result of proliferation introduced due to agronomic parameters, cold chain supply, and retail activities. The combined result of total coliforms and opportunistic pathogens found on the end-products indicates poor minimal processing, poor hygiene and sanitation standards. Lastly, Enterobacter cloacae, Staphylococcus aureus, Micrococcus luteus, Staphylococcus sciuri, Acinetobacter haemolyticus, Burkholderia cepacia, Psuedomona luteola, Escherichia coli, Citrobacter freundii and Serratia marcescens were tested again nine antibiotics. Multidrug resistance was observed with 79% resistance, this is a public health threat that points out challenegs regarding treatment of infections caused by these opportunistic and zoonotic pathogens. Rapid identification of antibiotics is essential and crucial for the development of effective antimicrobial compounds as well as prevention of antibiotic resistance. Necessary measures should be taken to reduce the level of contamination from small-scale farms to reduce antibiotic consumption in humans.
Access status: Open Access ,
Inhibitory effects of South African plants against mycotoxigenic phytopathogens
(Central University of technology, 2024-09) Mariri, Ntagi Gerald
Mycotoxigenic fungal strains pose a significant threat to food crops consumed by humans and animals, leading to reduced yields and compromised food quality as reported in almost 25% of maize products worldwide. The harmful effects following the ingestion of mycotoxin-contaminated food include inducing cancers, mutagenicity, immune suppression, and toxicities to target organs of the digestive, cardiovascular, and central nervous systems. Synthetic fungicides are associated with a high potential for toxic residues in food and the development of fungal resistance. Genetically modified crops can also reduce crop contamination. However, these strategies are inaccessible and expensive resources for most subsistence farmers. To address these issues, the use of plants as potential biopesticides to counter fungal infections on crops emerges as a possible solution to enhance food safety and security. This study aimed to determine the antifungal activities of Bauhinia galpinii N. E. Br., Combretum caffrum (Eckl. & Zeyh.) Kuntze, Markhamia obtusifolia (Baker) Sprague, and Maytenus undata (Thumb.) Blakelock, against mycotoxigenic fungi and potentially develop plant-based bio-fungicides. The leaves of the ethnobotanically selected plants were extracted using methanol and tested for antifungal activity against phytopathogenic strains of Aspergillus parasiticus, Aspergillus nomius, Fusarium verticilloides, Fusarium graminearum, Fusarium oxysporum, Penicillium haloterans and Cladosporium cladospoides. The antioxidant activities of the extracts were tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzthiazoline-6-suphonic acid) (ABTS) assays. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) cytotoxicity assay was used to investigate the effects of the extracts on the viability of the African green monkey kidney (Vero) cells and the human colorectal adenocarcinoma (Caco-2) cells. Additionally, the micronucleus test was used to examine the potential of these plants to induce genotoxicity in Vero cells. The identity and quantity of phytocompounds in the plant extracts were analysed using gas chromatography (GC-ToF-MS) mass spectrometry and liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis. The highest percentage extract yield was recorded from Combretum caffrum (23%), while Markhamia obtusifolia yielded 10.7%. Bauhinia galpinii methanol extracts had the lowest MIC value of 0.16 mg/ml against Furasium graminearum, Furasium oxysporum, Penicillium haloterans, and Cladosporum cladospoides at 24-hour incubation period. C. caffrum had a MIC value of 0.31 mg/ml against F. vercitilloides and F. graminearum. C.caffrum had the highest total activity (TA) of 1437.5 ml/g against the fungal pathogen, Aspergillus nomius. In the antioxidant studies, C. caffrum had good antioxidant activity against DPPH with 50% inhibitory concentration (IC50) value of 10 μg/ml, while B. galpinii had IC50 value of 50 μg/ml against free radicals of ABTS. Based on the ABTS/DPPH correlations (ADC), M. undata exhibited a notable ADC correlation of 2.33, which is over three-fold that of the ADC of ascorbic acid (control drug). Furthermore, all extracts were assayed for cytotoxicity and genotoxicity using the MTT and micronucleus assays, respectively. In the cytotoxicity studies, B. galpinii, C. caffrum, and M. undata extracts were cytotoxic to Vero cells at 500 μg/ml. C. caffrum and M. undata extracts demonstrated cytotoxic effects on human colorectal adenocarcinoma cells in a dose-dependent manner. C. caffrum extract significantly reduced cell viability by up to 89.61% at the highest concentration of 500 μg/ml. M. undata extract was also cytotoxic at the highest tested concentration of 500 μg/ml. B. galpinii extracts increased the viability of the cancer cells, indicating a potential stimulation of cell proliferation. The extract from M. obtusifolia had no effect on the cells at the tested concentrations of 250 and 500 μg/ml. These findings suggest that C. caffrum and M. undata extracts have potential as cytotoxic agents against colorectal adenocarcinoma cells, while B. galpinii extracts may not be suitable for cancer treatment. All tested plant extracts were genotoxic at the highest tested concentration of 500 μg/ml. C. caffrum showed genotoxicity at 250 μg/ml and reduced cell numbers to less than 50% of the control at 500 μg/ml, indicating its significant cytotoxic potential. Three of the four medicinal plants reported a higher phenolic content (TPC) compared to their total flavonoid compounds. These higher TPC contents may well explain the antimycotoxigenic and antioxidative ability of the medicinal plants selected for the current study. The GC-ToFMS analysis of the selected medicinal plants revealed that all the extracts contained Hexadecanoic acid (HA) and methyl ester. B. galpinii and C. caffrum exhibited the presence of lupeol, while M. obtusifolia and M. undata contained phytol. Kaempferitrin was identified following the LC-TOF-MS analysis of both B. galpinii and M. obtusifolia. Quercitrin was identified from C. caffrum, while rutin and pisumionoside were identified from M. undata. Overall, the study concluded that the strong inhibitory effects against various fungal pathogens shown by some of the tested plants indicate that investigating plants as potential solutions for fungal infections in crops offers a promising avenue to enhance food safety and security in developing and underdeveloped countries. Therefore, it is important to intensify efforts to explore the use of plants as potential biopesticides. To further advance the findings of the current study, continued research and safety assessments of the tested South African plant extracts are essential to fully exploit their potential benefits in agriculture and healthcare while mitigating any risks to human health and the environment.
Access status: Open Access ,
Microbial profiling of food contact surfaces in hospitals at Maseru Lesotho
(Central University of technology, 2025-07) Maliehe, Salmina Mankomane
Food handlers play a key role in ensuring food safety throughout the food production, processing, storage, and preparation chain. In food service establishments, the common sources of microbial contamination reportedly originate from dirty food contact surfaces, poor personal hygiene practices, and inappropriate storage temperatures. Contamination primarily arises from food contact surfaces such as utensils, equipment, and food handler hands or clothing. The overall purpose of this study was to investigate microbial contamination of food contact surfaces in hospital kitchens in the city of Maseru, Lesotho. The objectives were to assess food handlers’ knowledge, attitudes, and hygiene practices and to characterize prevalent hospital foodborne pathogens associated with food contact surfaces. The study also evaluated the efficacy of common disinfectants against microorganisms and investigated the production of extended-spectrum beta-lactamase (ESBL) against Gram-negative bacteria. The study was conducted in five hospitals involving food handlers ranging between 2-7 per hospital. A total of 26 food handlers participated in the study. A structured questionnaire that had been derived from previous studies was used to assess the food handlers’ knowledge, attitudes, and practices (KAPs). The microbial isolates were identified to specie level by use of biochemical test kits (Staph API, RAPID ONE and RAPID NF Plus). The identified Gram-negative bacteria were subjected to a series of antimicrobials in order to determine the susceptibility profile using the Kirby-Baur disc diffusion method. The phenotypic tests for ESBL detection were used to test for ESBL production with subsequent double disc synergy test used as a confirmation method. Isolates were further subjected to the Kirby-Baur disc diffusion method to establish susceptibility to common disinfectants. Subsequently, the minimum inhibitory concentrations and the minimum bactericidal concentrations were determined by using the in-vitro susceptibility test employing 96-well microtiter plates. More female (n=23; 88%) than male (n=3; 12%) food handlers participated in the study. The majority of these food handlers (n=25; 96%) were aware that proper cleaning and sanitization of utensils decreases the risk of contamination. Although 54% (n=14) of the food handlers reported that they had received training, none of the food handlers were could provide formal documentation to verify their training. However, there was general consensus (n=26; 100%) that food safety training is important. Despite the evident lack of knowledge regarding refrigeration and holding temperatures for hot ready-to-eat foods, the food handlers agreed that refrigerators/freezers should be checked regularly to reduce the risk of contamination. The microbial analysis study revealed that food contact surfaces, including food handlers’ hands, yielded high counts of all detected microorganisms (TVC, total coliforms, Escherichia coli, Staphylococcus sp., Salmonella sp., and Pseudomonas sp). This indicated a discrepancy between knowledge of food processing and of environmental and personal hygiene. In natural settings, microorganisms can be introduced in various ways by means of people, food, water bioaerosols, and domestic animals. The acquisition of microorganisms such as Stenetrophomonas maltophilia, Sphingomonas paucimobilis, and Myroides odorantum that are predominantly associated with clinical infections was evidence of possible cross-contamination from the hospital wards to the kitchen. The investigation of the extended-spectrum beta-lactamase (ESBL) production of Gram-negative bacteria revealed positive ESBL production in 43% of the microorganisms. This is an important finding given that the ESBL-producing genes can be transferred within niches and the production of these enzymes confers resistance to most commonly used antibiotics. Additionally, there was a 71% multidrug resistance among isolates and none of the microorganisms tested showed susceptibility to current antibiotics. However, a 100% resistance to penicillin was noted which affirms the growing resistance of microorganisms to common antibiotics and the need for new treatment options. The high resistance profile demonstrated by microorganisms in this study can be attributed to personal prescription of antibiotics as these antibiotics are available at pharmacies without a doctor’s prescription. The investigation of the efficacy of the disinfectants against the Gram-negative and Gram-positive bacteria revealed that both disinfectants 1 and 2 exhibited antimicrobial properties against the tested microorganisms. However, disinfectant 2 was found to have bactericidal effect against only the Gram-positive bacteria. The results therefore indicated that although there was an antimicrobial effect of disinfectant 2 against Gram-negative bacteria, disinfecting surfaces with such a disinfectant will not render the surface free from Gram-negative bacteria.