Thesis

Studies on disease prevention and control, decontamination and sterilization, microbial adaptive responses and survival, alternative therapies, and sustainability

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Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T17612
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Department, School or Faculty
Abstract
  • This thesis describes my independent research studies starting in 1996 on five related areas that have advanced disease prevention and control including sustainable technologies to meet significant societal challenges. There are ever increasing demands for specialist foods and sophisticated devices to meet complexities of modern society including serving vulnerable groups. Whilst there is an expanding volume of published literature on developing food production, and to a much lesser degree medical devices, there is a need to understand why traditional and emerging decontamination and sterilization modalities work and what conditions or circumstances operating at the interface between microbial destruction and maintaining a desired product functionality could support microbial survivors and potentially foodborne or iatrogenic-mediated infection. There is also a dearth in knowledge surrounding the real-time detection of viable fastidious pathogenic microorganisms (such as complex parasites or drug-resistant fungi) post selection of appropriate technologies to safely treat foods and to decontaminate complex reusable medical devices. There is also a dearth of published information on appropriate cellular and molecular indicators to inform critical mechanistic information underpinning testing, verification and validation of new decontamination technologies. Elucidating holistically, the key parameters governing reliable and effective decontamination, provides evidence-based data to inform next-generation products from design thinking to automation in order to meet emerging societal needs. The first section provides critical new insights and knowledge on conditions promoting the potential survival of microbial pathogens in sensitive foods such as reconstituted foods destined for vulnerable populations. It describes preparation and storage-abuse conditions promoting adaptive microbial survival and toxin production leading. It describes occurrence of such abuse conditions in hospital prepared feeds in a HIV ward along with implemented of my recommended solutions that informed new guidelines of practice and helped to mitigate against future food-borne illnesses. This section characterizes processing conditions promoting the occurrence of atypical pathogens in sensitive foods, such as thermal-stresses leading to atypical cellular appearance and virulence factor expression Listeria monocytogenes that also enabled survival in human polymorphonuclear leukocytes. The second section elucidates the first reporting on reliable and repeatable operational conditions underpinning non-thermal processing technologies (pulsed UV light, pulsed-plasma gas-discharge, pulsed electric fields), which also encompasses key mechanistic knowledge on critical cellular and molecular determinants governing irreversible microbial cell death. Commensurate studies report on development of alternative biomarkers to monitor and evaluate real-time disinfection performance including first report of a combined cell culture-qPCR assay for complex entero-parasites. New methodologies for toxicological end-point determinations in processing technologies are described. First reporting on microbial kinetic inactivation and modelling for non-thermal technologies. Studies also elucidate appropriate treatment dose for effective killing of biological indicators including development of vaporized hydrogen peroxide as a new thermal sterilization modality for medtech. The third section elucidates and develops non-thermal decontamination and sterilization technologies at commercial scale for established and new applications including for medical devices, food/feed, and for pollination industry (such as for decontaminating heat-sensitive pollen of complex pathogens fed to bees). Depending on the application, these studies include technologies encompassing x-ray, electron-beam, gamma-irradiation, pulsed UV and the co-development of real-8578/-+parametric release for treated products. Understanding the holistic interplay of all applied and inimical stresses governing effective microbial lethality defines critical knowledge including desirable end-to-end sterility assurance conditions ranging from elucidation to verification and validation of technological applications that meets safety. This section describes first classification system for effective cleaning of complex features in reusable medical devices and revisits efficacy of Spaulding’s classification for device sterilisation and patient safety using this combinational new cleaning method. A holistic subject-matter knowledge of decontamination helps society meet unforeseen threats such as my elucidation and the first published recommendation of appropriate sterilization technologies and conditions for the safe reuse of PPE arising from critical supplying chain shortages during COVID-19 pandemic along with for sustainable waste management. Studies advance shellfish depuration and decontamination for recalcitrant fastidious norovirus pathogens attached to bivalve tissue. The fourth section elucidates and develops novel alternative therapies and approaches for combatting antimicrobial-drug resistant (AMR) pathogens including bacteria and fungi, such as for lung delivery and for animal feed applications. Studies also address diagnostics for AMR pathogens that are at crisis point for society linked to decontamination. Studies also address elucidation of alternative antimicrobial and biofilm-disrupting bioactives used synergistically and in combination, yet tolerant of and suitable for medical device production-processes for smart coating applications. The last section describes development of sustainable innovation including use of appropriate disinfection technologies. This includes first studies on development of an integrated multi-trophic aquaculture system in the peatlands aligned with zero-waste, zero pollution and climate action principles. It addresses digital transformation including new ‘in-field’ real-time monitoring and combined use of bioinformatics and next-generation sequencing to advance sustainable food innovation. It develops and applies new models including life cycle assessment and ecological tools.
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DOI
Embargo Note
  • The electronic version of this thesis is currently under moratorium due to a licensing issue. If you are the author of this thesis, please contact the Library to resolve this issue.

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