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Occurrence of mycotoxins, diversity of aspergillus section flavi, along the cassava value chain, and innovative strategy for aflatoxin reduction during storage in Uganda
No full textCervini, Carla - Associate SupervisorThis thesis (1) Investigated the cassava handling practices along the value chain in two contrasting cassava production and consumption regions (each with four districts) of Uganda, to identify critical points that may potentially contribute to mycotoxin contamination, understand the knowledge extent about mycotoxins, and identify and collect the major consumed cassava products, (2) determined the occurrence and distribution of mycotoxins in major cassava products to identify the levels of mycotoxin contamination along the major value chain actors (farmer and wholesaler and processors) from samples in different regions, (3) assessed the fungal diversity, and identity of dominant fungal species (Aspergillus section Flavi ) isolated from soil and cassava products from Uganda, and (4) developed an innovative strategy with potential to completely eliminate occurrence of aflatoxins during storage. One of the major outputs of this thesis was to develop a Hazard Analysis and Critical Control Point plan for the cassava value chain in Uganda.
Key practices identified as likely to predispose cassava to mycotoxins contaminations include peeling cassava on bare ground, direct ground drying, inadequate storage conditions, and poor processing techniques. Data from 210 individual interviews, 34 key informants and 4 focus group discussions revealed that majority (51 %) of farmers peeled cassava directly on bare ground, resulting in direct contact with soil that potentially harbours mycotoxin-producing fungi, such as Aspergillus section Flavi. During post-harvest handling, 51.6 % of farmers dried cassava chips directly on bare ground. Nearly, all (95.2 %) of wholesalers packed cassava chips in local gunny bags and placed them on ground instead of pallets. In the processing of cassava chips into flour, only one of the 14 processing machine was certified by the Uganda National Bureau of Standards. The greatest proportion (73 %) blended cassava flour with flour from mycotoxin-susceptible crops mainly maize, millet, and sorghum. Most (96.2%) of the people along the cassava value chain did not understand what the term mycotoxins meant, but 56% were familiar with the term aflatoxins. Of the cassava value chain actors aware of mycotoxins, 82.9 % knew of methods for reducing aflatoxin contamination, but only 40.9 % were putting such methods into practise. Cassava chips and flour were the predominantly consumed cassava products by 95% of respondents and were assessed for mycotoxin contamination.
A total of 192 samples of cassava products (96 flour and 96 chips) analysed using LC-MS/MS revealed that all positive samples irrespective of their origin (flour or chips), exhibited aflatoxin B1 (AFB1) levels exceeding the EU regulatory threshold of 5 µg/kg. For the first time, the study reported the highest levels of AFB1 in Uganda’s cassava, ranging from 13.1 to 298 µg/kg in flour and 2.24 to 420 µg/kg in chips. The sum of fumonisins (FB1+FB2), zearalenone (ZEN) and deoxynivalenol (DON) were significantly (P<0.05) higher in cassava flour (14.3 µg/kg; 3.71 µg/kg; 25.1 µg/kg) compared to chips (6.54 µg/kg; 1.25 µg/kg; 0.25 µg/kg), respectively. Cassava flour samples from farmers exhibited significantly (P<0.05) higher mean concentrations of AFB1 (27.1 µg/kg), total aflatoxins (78.2 µg/kg) and ochratoxin A (79.6 µg/kg) in contrast to wholesalers, at 8.91, 5.79 µg/kg and 2.44 µg/kg, respectively. The risk of AFB1 exposure to cassava consumers was also determined and revealed that, cassava consumers in Northern Uganda are at a higher risk of Hepatocellular Carcinoma (HCC)-a type of liver cancer, with an estimated 2.06 cancer cases per 100,000 individuals per year compared to those in Eastern Uganda at 0.25.
Given that aflatoxins were the most dominant mycotoxins in Uganda’s cassava products, it was paramount to identify the aflatoxin producing species for targeted intervention. To identify the aflatoxin producing species in Uganda’s cassava, a total of 288 samples (soil-48, tubers-48, chips-96, and flour-96) were assessed for the number of colony forming units (CFU/g) growing on
Dicloran-18-glycerol agar (DG-18). The most dominant fungi (Aspergillus section Flavi) were further assessed for its aflatoxigenicity, and a polyphasic approach was followed to identify the species. Aspergillus (84%), Penicillium (2.1%), Fusarium (3.62%), and Rhizopus (9.9%) were frequently observed fungal genera. Within the Aspergillus genus, species belonging to Aspergillus section Flavi were significantly (P=0.021) the most dominant with highest CFU/g of 1.48 ×105. A total of 77/162 (47.5%) was aflatoxigenic. 22/27 isolates from soil were aflatoxigenic, labelling it a strong reservoir for aflatoxigenic species. Following polyphasic approach, 64% (33/52) of the isolates were Aspergillus flavus, 25% (13/52) Aspergillus parasiticus, 8% (4/52) Aspergillus novoparasiticus, one Aspergillus minisclerotigenes, and another Aspergillus tamari. Three distinct Aspergillus isolates were identified, including one identified as Aspergillus tamari, which produced AFB1, AFB2, and AFG1 but not cyclopiazonic acid (CPA). In addition, two Aspergillus parasiticus isolates were found to produce only AFB1, AFB2, and CPA. These species will be sent for confirmation to Westerdijk Institute for further investigation. Thus, to manage aflatoxins in Uganda, there is need to develop innovative solutions specifically targeting Aspergillus section Flavi isolates with strong focus on Aspergillus flavus.
In this study we investigated the efficacy of sodium metabisulphite on reducing aflatoxins during storage. Both in vitro laboratory and field experiments were conducted. In vitro involved growing three highly aflatoxin-producing species (A. flavus, A. parasiticus, and A. minisclerotigenes) in cassava-based media at different water activity (0.90, 0.95, 0.99 aw) at different concentrations of sodium metabisulphite (0, 125, 250, 500, 1250, 1500 mg/L) for 15 days. While field experiments were set up in Uganda’s field conditions in districts with different climatic conditions. The initial fungal load, and AFB1 levels were determined. In vitro results showed that NaMBS completely inhibited the growth of A. flavus, A. parasiticus, and A. minisclerotigenes—reducing growth (colony diameters) from 48 mm, 45 mm, and 20 mm, respectively, to zero—at a concentration of 1250 mg/L of sodium metabisulphite.
Field experiments were set up in Uganda’s field conditions in districts with varying climatic conditions. The initial fungal load, and AFB1 levels were determined. The results in field conditions revealed that NaMBS had a significant potential in reducing both the fungal load and completely reducing initial AFB1 concentration. Cassava chips placed in traditional bags without NaMBS treatment showed the highest levels of AFB1 levels (146.6 µg/kg) and fungal load of 20.4 mean cfu/g ×10^5 indicating that traditional bags, when untreated with NaMBS, do not significantly reduce AFB1 and fungal load. While PICS bags without NaMBS treatment also exhibited a considerable amount of AFB1 (91 µg/kg) and fungal load of 6.1 mean cfu/g ×10^5. However, the application of NaMBS treatment led to a drastic reduction in AFB1 from 185 µg/kg to 10.9 µg/kg (94.5% reduction rate) and fungal load 3.5 mean cfu/g ×10^5(82.8% fungal reduction) for traditional bags and 0.23 µg/kg (99.9% reduction rate) and fungal load of 1.9 mean cfu/g ×10^5 for PICS bags. These findings suggest that the addition of NaMBS treatment is highly effective in reducing the fungal load and AFB1 in both types of bags. This thesis provides a major contribution towards management of mycotoxins especially aflatoxins within cassava production in Uganda.
Finally, based on Hazard Analysis and Critical Control Point (HACCP), out of the six main steps of cassava flour production which include harvesting, peeling, milling, storage, packaging and drying, the critical control points are: storage, packaging, and drying on bare ground. Harvesting, peeling and milling are not critical control points (CCPs) but possess potential areas of contamination that should be prevented. Key ecophysiological factors that should be monitored to manage the CCPs below the control limits include moisture content (ideally below 13%), water activity (aw between >0.6), and relative humidity (preferably below 65%). Also, total aflatoxin levels should be kept below 10 µg/kg. Implementing good handling practices and good agronomic practices are also vital to manage these CCPs.PhD in Environment and Agrifoo
A review of flexible robotic gripping systems
No full textThe rapid advancement and expanding application of robotics in various sectors necessitate the development of versatile and efficient gripping systems. Robotic grippers, serving as the primary interface between robots and the physical world, are pivotal for the success of robotic applications ranging from industrial automation to delicate tasks in healthcare. This paper delves into the diverse landscape of robotic grippers, examining their design principles, material choices, and the intricate balance between flexibility and strength required to cater to a broad spectrum of operational demands. It further explores the spectrum of actuation mechanisms that empower these grippers, from traditional electric and pneumatic systems to cutting-edge soft robotics technologies that offer unprecedented adaptability and safety. The integration of sensors within grippers, enhancing their intelligence and autonomy, is also scrutinized, alongside a critical evaluation of control strategies that range from conventional PID controllers to sophisticated machine learning algorithms. In addition, this paper emphasizes the significance of real-time control and adaptation in ensuring robots’ ability to respond promptly to environmental changes, leveraging fast data processing and feedback mechanisms for improved performance. The aim of this comprehensive review is not only to provide a foundational understanding of the current state of robotic gripper technology but also to highlight key considerations and emerging trends that will shape the future of robotic manipulation. Through this exploration, the paper seeks to equip designers, engineers, and researchers with the insights needed to innovate and advance the field of robotic gripping systems.Frontiers in Manufacturing Technolog
Biotechnology strategies for bioactive compound extraction
No full textThe marine environment is a relatively unexplored source of bioactive compounds that can be used in several industries in various ways. Some organisms live in harsh environmental conditions, resulting in complex compounds with unique biological properties. One of the main challenges for their application into the industry is their extraction, one of the most crucial stages in developing products containing bioactive compounds from marine sources. Soxhlet extraction is the most common method applied at lab and pilot scales to obtain compounds from any natural source. However, this method is based on using solvents that can be harmful to the environment and affect the biological properties of the compounds. For this, biotechnological extraction techniques such as fermentation, enzyme-assisted extraction, and molecular tools have emerged as alternatives to traditional methods that enable the extraction of high-quality bioactive compounds without using harmful solvents. Besides, these technologies have shown great potential to be applied at the industrial scale once the optimization of the process has been carried out. This chapter focuses on the potential use of biotechnological tools for extraction, considering the factors that affect the yields and downstream process of marine-derived bioactive compounds for further applications in the industry.Bioactive Compounds Extraction from Marine Resources and Waste
Academic institution extensive, building-by-building wastewater-based surveillance platform for SARS-CoV-2 monitoring, clinical data correlation, and potential national proxy
No full textA correction is included with this paper.In this work, we report on the performance of an extensive, building-by-building wastewater surveillance platform deployed across 38 locations of the largest private university system in Mexico, spanning 19 of the 32 states, to detect SARS-CoV-2 genetic materials during the COVID-19 pandemic. Sampling took place weekly from January 2021 and June 2022. Data from 343 sampling sites was clustered by campus and by state and evaluated through its correlation with the seven-day average of daily new COVID-19 cases in each cluster. Statistically significant linear correlations (p-values below 0.05) were found in 25 of the 38 campuses and 13 of the 19 states. Moreover, to evaluate the effectiveness of epidemiologic containment measures taken by the institution across 2021 and the potential of university campuses as representative sampling points for surveillance in future public health emergencies in the Monterrey Metropolitan Area, correlation between new COVID-19 cases and viral loads in weekly wastewater samples was found to be stronger in Dulces Nombres, the largest wastewater treatment plant in the city (Pearson coefficient: 0.6456, p-value: 6.36710−8), than in the largest university campus in the study (Pearson coefficient: 0.4860, p-value: 8.288x10−5). However, when comparing the data after urban mobility returned to pre-pandemic levels, correlation levels in both locations became comparable (0.894 for the university campus and 0.865 for Dulces Nombres). This work provides a basic framework for the implementation and analysis of similar decentralized surveillance platforms to address future sanitary emergencies, allowing for an efficient return to priority in-person activities while preventing university campuses from becoming transmission hotspots.This research was funded by the Fundación FEMSA project entitled “Unidad de respuesta rápida al monitoreo de COVID19 por agua residual” (grant number NA to RPS). This work was supported by Tecnologico de Monterrey through the project Challenge-Based Research Funding Program 2022 (Muestreador Pasivo I026 - IAMSM005 - C4-T1 – T to JESH). Research time for R Parra Saldivar is funded by Research England, UKRI.PLOS Global Public Healt
Building a Governance Reference Model for a specific enterprise: addressing social challenges through structured solution
No full textSocietal challenges are inherently complex and multi-tiered, arising from the interplay of diverse stakeholders with a spectrum of purposes and different perceptions and expectations, interdependent systems, and dynamic contextual factors that transcend single domains or disciplines. This paper presents a novel approach to developing a Reference Model of Governance tailored to a specific complex, multi-organisational enterprise facing socially complex challenges. Drawing on Angyal’s systems framework, the model introduces a three-dimensional structure with vertical, progression, and transverse dimensions, integrated within a holistic contextual whole. By mapping selected systems methodologies, including Soft Systems Methodology (SSM), Viable System Model (VSM), System Dynamics (SD), and dependency modelling, to these dimensions, the model offers a pragmatic, structured way to explore and regulate complex organisational behaviour. It enables collaborative inquiry, supports adaptive governance, and enhances the enterprise’s ability to address dynamic societal problems such as health, education, and public service delivery. The result is a governance reference model that captures both the operational and contextual realities of the enterprise, providing actionable insight for strategic design or diagnostic intervention. The novel approach is grounded in systemic and critical systems thinking and emphasises the use of methods for understanding to develop a common and shared understanding of the enterprise context and to surface multiple stakeholder perspectives.System
Applications of artificial intelligence in the dairy Industry: from farm to product development
No full textThe dairy industry faces increasing demand for enhanced productivity, sustainability, and innovation. Artificial Intelligence (AI) has emerged as a transformative tool capable of addressing these challenges by enabling data-driven decision-making across the dairy supply chain. AI integrates machine learning (ML), big data analytics (DA), and predictive algorithms (PA) to optimize processes, improve efficiency, and foster innovation. This review examines the diverse applications of AI in the dairy industry, including dairy farming, processing, and product development. In this context, an overview of AI, including ML, DA, and various algorithms used in these processes, is discussed. A major discussion has been provided on AI for animal performance (e.g., disease detection, reproductive management, milk yield enhancement, nutrition) and sustainable practices (e.g., emission control, precision farming). Furthermore, AI in dairy processing (quality control and process optimization) and product development (flavor and texture prediction, and customized products) has been developed. Finally, the challenges of AI integration, including data privacy, ethical considerations, and technical barriers, are reported. The findings indicate that AI revolutionizes traditional practices by enabling precise farming, energy-efficient processing, and the creation of customized, high-quality products. Despite its transformative potential, challenges, such as ethical concerns and technological limitations, must be addressed.This research was supported by Mahidol University, Thailand. Dr. Sandeep Jagtap would like to acknowledge the FORCE (Center for food system resilience and competitiveness) at Lund University.Computers and Electronics in Agricultur
Synthesis and manufacturing of fibre-reinforced vitrimeric composites based on epoxy and benzoxazine matrices
No full textThakur, Vijay Kumar - Associate SupervisorEpoxy and polybenzoxazine vitrimers have been synthesised in this study and
used as composites matrices to assess their self-healability. A disulphide bond-
endowed reference epoxy vitrimer was formulated based on the established
chemistry of diglycidyl ether of bisphenol A and 4-aminophenyl disulphide. Also,
a new high-temperature benzoxazine vitrimer (coded BH-A) was synthesised
through solventless one-pot method, featuring disulphide bond. The thermal,
rheological, cure kinetics and relaxation behaviour of the vitrimers was studied
as well as the mode I delamination response of their carbon fibre composites
before and after healing. Both the epoxy and benzoxazine systems are high-
temperature systems with a glass transition temperature of 163°C and 155°C,
respectively and topology freezing transition temperatures of 149.5°C and 78°C,
respectively. The cure kinetics of both resins are autocatalytic and were modelled
with an average reaction rate error of 5.2% and 14.1% for the epoxy and
benzoxazine systems, respectively. The rheological behaviour of the epoxy
vitrimer allows manufacturing of composites by liquid moulding, whereas the
rheological behaviour of benzoxazine vitrimer is appropriate for manufacturing of
composites through resin film infusion. The epoxy system undergoes full stress
relaxation in 16 seconds at 220°C and can be healed at this temperature under
a pressure of 50 bar in 90 minutes, whereas the benzoxazine system relaxes fully
within 5 seconds at 190°C and can be healed at this temperature with a pressure
of 4 bar in 30 minutes. Fracture toughness recovery in both composites depends
on the historical crack opening prior to healing and follows an exponential decay
from a value of 100% at the previous crack tip to about 13 – 20 % at the position
of maximum previous crack opening. The self-healing of the benzoxazine
composite is superior to that of the epoxy system, as it is achieved within the
practically realistic composite manufacturing conditions.PhD in Manufacturin
Fusarium graminearum and zearalenone in wheat: a water activity–temperature model
No full textZearalenone (ZEN) is a nonsteroidal estrogenic mycotoxin produced primarily by Fusarium graminearum, posing significant threats to agricultural grain production. When ZEN levels exceed regulatory limits, grains face rejection, and its harmful effects on the female reproductive system raise health concerns. Despite its importance, there is a lack of information on the ecophysiological conditions that promote F. graminearum colonisation and ZEN production in wheat grains. This study aimed to develop and validate predictive models for the growth of F.graminearum and ZEN accumulation in wheat. For this purpose, two strains isolated from wheat were inoculated in agar wheat-based medium supplemented with glycerol to adjust the water activity (aw) to five different values of 0.88, 0.91, 0.94, 0.97 and 0.99. The cultures were incubated at 4, 6, 8.5, 15, 20, 25, 30 and 35 °C, the colony growth was measured daily, and ZEN accumulation assessed at day 10, 20 and 30. To analyse the growth kinetics of F. graminearum, the fungal growth rate (μ) and lag time (λ) were calculated, applying the Cardinal/Rosso, Davey, and Gibson models. These techniques, commonly used in secondary modelling, were enhanced through variable transformation, with the square root transformation yielding optimal results in the Cardinal models. The outcome showed probabilistic model accuracy for growth ranging 65–79 % and ZEN production ranging 45–77 % on internal and external data set. Optimum temperature for ZEN production was 25–30 °C in media and wheat. In wheat, a higher aW was required for both growing (0.92 aw) and ZEN production compared to media (0.90 aw). Probabilities of growth over 80 % were predicted in the range of 0.90–0.95 aw at 16–34 °C after 30 days. In conclusion, to avoid mycotoxin contamination in wheat an aw < 0.89 should be maintained, and temperatures in the range 18–31 °C should be avoided (P < 0.5). The integration of predictive models into decision support systems could assist farmers in identifying pre-harvest contamination risks and in optimising harvesting and drying practices to minimise post-harvest contamination. This study highlights the importance of understanding the ecophysiological profiles of mycotoxigenic species like F. graminearum to mitigate contamination risks and optimise storage conditions in wheat.This project (MyToolBox) has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 67801.Fungal Biolog
Thermally enhanced biodegradation mechanisms of trichloroethene and benzene co-contaminants in groundwater: insights into microbial functional gene enrichment and biogeochemistry
No full textA series of thermally enhanced biodegradation (TEB) experiments at varying temperatures (15, 30 and 45 °C) were conducted to evaluate their effects on the biodegradation kinetics of trichloroethene (TCE) and benzene co-mingled contaminants using indigenous microbial consortiums. Results demonstrated that the highest TCE biodegradation rate, 0.35 μ mol L⁻¹ day⁻¹, with a half-life of 49 days, was observed at 30 °C, whereas the biodegradation of benzene was enhanced to a less extent. The functional gene analysis results revealed that increased tceA and tmoA genes contributed to enhanced TCE and benzene biodegradation at 30 °C, respectively. Additionally, the reduced vcrA and bvcA abundance and lack of effective electrons may attribute to the cis-1,2-dichloroethylene stalling and low concentration of ethene. Moreover, the biogeochemical analyses confirmed that elevated temperature promoted denitrification and sulfate reduction processes, which expedited methanogenesis, leading to the enhanced dechlorination of TCE. Additionally, the abiotic degradation of TCE facilitated by FeS, evidenced by acetylene and ethene detections, also contributed to the observed enhanced TCE degradation. The study shed lights on the role of temperature in enriching microbial functional gene and influencing biogeochemical conditions for the simultaneous anaerobic biodegradation of TCE and benzene. The findings demonstrated that optimized thermal treatments can effectively bioremediate chlorinated and aromatic hydrocarbons in groundwater.This work was funded by the National Key Research and Development Program of China (No. 2019YFC1805700 and No. 2019YFC1805703), the National Natural Science Foundation of China (NSFC)-EU Environmental Biotechnology Joint Program (No. 32061133001). We acknowledge the cooperation between China and the EU through the EiCLaR project (European Union’s Horizon 2020, N°965945).Journal of Hazardous Material
Unpacking drought impacts and adaptive strategies in Morocco – perspectives from small-scale farmers
No full textCorrigendum to ‘Unpacking drought impacts and adaptive strategies in Morocco – perspectives from small-scale farmers’ [Int. J. Disaster Risk Reduct. 128 (2025), 105732]
https://doi.org/10.1016/j.ijdrr.2025.105754Droughts in North Africa are increasing in frequency and severity. The most vulnerable include small-scale farming communities and the associated small businesses with wide-ranging impacts and demands on local communities, food production, water allocation, and energy requirements. Our solution-orientated study supports the mitigation of impacts and the management of droughts in two case study areas within Morocco. A 2-day workshop was conducted to engage with local farmers in Settat and El Jadida to better understand the drought impacts and associated adaptive strategies. A Fuzzy Cognitive Mapping (FCM) approach was used to actively engage and interact with the farmers and to gain an understanding of the interconnections between drought, coping mechanisms, adaptation strategies, and issues to their livelihood and as seen through their experiences. The perspectives give new insights into where the policy interventions for the most impact in the system might be.Official Development Assistance, UK Research and Innovation, Engineering and Physical Sciences Research CouncilThe authors wish to acknowledge the support of GCRF and Newton Fund as well as the valuable support of our project partners at Mohammed VI Polytechnic University (UM6P), National Institute of Agronomic Research (INRA), and Al Moutmir team members in Settat and El Jadida regions of Morocco, in facilitating and conducting the workshops. The indicators used in these workshops are part of the Management of Disaster Risk and Societal Resilience (MADIS) project which is funded by Belmont Forum and UKRI-EPSRC (Grant no.: EP/V006592/1)International Journal of Disaster Risk Reductio