https://www.um.edu.mt/library/oar/handle/123456789/116601 2026-04-14T03:47:19Z https://www.um.edu.mt/library/oar/handle/123456789/141775 Title: Prevalence of legionella pneumophila from water sources in the Maltese Islands Abstract: This project has dealt with the prevalence of Legionella pneumophila and other indicator organisms from water sources used in educational, industrial, health institution and recreational environment in Malta and Gozo. A previous study related to the detection of Legionella species in Health Institutional facilities had been performed in 2005 but it did not include the current General Acute Teaching Hospital (GATH) included in this study which accepted patients in late 2007. Another study involving testing of water samples for Legionella was carried out in 2013 and it involved testing of 27 samples from the Maltese Islands which included five water samples from water fountains (Blundell, 2014) . Other studies on Legionella recorded did not involve laboratory-based tests. According to the Annual Epidemiological Report published by the European Centre for Disease Prevention and Control (ECDC) for 2019, there were 5 cases of Legionnaires’ disease recorded in Malta but none resulting in death (ECDC, 2021) [...] Description: M.Phil.(Melit.) 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/119534 Title: Development of protocols and quantification of mycotoxin contaminants of bakery flours in the Maltese market Abstract: Mycotoxins, secondary toxic metabolites produced by fungi under favourable conditions, have long raised concerns as contaminants in various flours, including wheat, wholemeal, rye, and maize, due to their detrimental effects on both human and animal health. This study addressed a knowledge gap by conducting the first survey of mycotoxin contamination in flours available in the Maltese market. The primary objective was to develop and validate in-house methods, while also identify and quantify mycotoxins present in flour samples sourced from supermarkets, milling facilities, and bakeries, specifically targeting products utilized in bread making and bakery processes. A survey in 16 flour samples was undertaken, utilizing high performance liquid chromatography coupled with fluorescent and photodiode detectors (HPLC-FLR-PDA) for the quantification of mycotoxin. OTA, DON, AF, ZEA, T-2, HT-2, FUM, and PAT were the key mycotoxins examined. Notably, the co-occurrences of mycotoxins were widely observed; however, AFs and FUM were absent from all samples. While common mycotoxins, including DON, T-2, and HT-2, were detected, the first was found below the maximum limits specified by the EU. The presence of patulin aligns with the prevalence of Penicillium contamination on the Maltese Islands. This finding highlights the need for more awareness and targeted surveillance strategies to accurately assess the true extent of mycotoxin levels in products circulating within the Maltese market. In conclusion, this first study gives an indication of the types of mycotoxins present in Maltese flours. The implications extend to both public health and food safety fields, prompting further investigations and the implementation of robust surveillance measures to ensure the accurate monitoring and control of mycotoxin levels within the local food supply chain. Description: M.Sc.(Melit.) 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/119501 Title: Genotoxic assessment of plasma activated solutions on N/TERT1 and N/TERT2G human keratinocytes Abstract: Several disease outbreaks that occurred in relatively recent times have highlighted the threatening danger that fast-spreading pathogens can cause in an unprepared world. Even though current methods of sanitisation have proven to be effective in disinfecting surfaces, equipment and hands, they are far from being the ideal sanitizer. Plasma-activated water (PAW) produced from cold atmospheric plasma (CAP) has the potential to be an efficient and better replacement for the common alcohol sanitisers used. The possibility to produce it on site, with fewer raw substances and adverse reactions, make it an ideal candidate for a universal sanitiser if proven to be medical-grade and effective against most pathogens. This study aimed at evaluating; (i) the mutagenic potential of hydrogen peroxide and PAW; (ii) the effect on cell viability of N/TERT 1 and N/TERT 2G cells after exposure to these two compounds; (iii) the oxidative stress imposed on the N/TERT cells after exposure to PAW and hydrogen peroxide and (iv) the genotoxic potential of the compounds on the keratinocyte cells through the change in replicative index and formation of micronuclei. A 30 min incubation protocol was used for the Ames test utilising S. enterica Typhimurium TA 98, S. enterica Typhimurium TA 100, S. enterica Typhimurium TA 1535, S. enterica Typhimurium TA 1537 and E. coli WP2 trp uvrA strains which resulted in no mutagenicity caused by either of the compounds. Exposure of both cell lines to hydrogen peroxide and PAW resulted in no decrease in cell viability upon exposure of up to 5 min as well as a decrease in 8-oxodG production, a biomarker of oxidative stress when compared to the negative control. A reduction in the replicative index was recorded when cells were treated with both media containing the test compounds with no formation of micronuclei recorded. This study demonstrated the potential use of PAW as a hand sanitizer for short exposure times of up to 5 min. Description: M.Sc.(Melit.) 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/117409 Title: Antimicrobial activity of plasma activated water against E. coli NCTC 12900 planktonic cells and biofilms formed on polystyrene surfaces Abstract: Background: Biofilm formation is the main cause contributing to an increase in foodborne illnesses. However, this may be prevented by using novel disinfection methods such as Plasma Activated Water (PAW), known for having strong antimicrobial properties. This study aims to develop bacterial biofilms under conditions similar to those encountered in the food industry, namely in polystyrene surfaces, and to evaluate the disinfection ability of PAW. Methodology: PAW was produced at atmospheric pressure using a copper electrochemical cell, and the pH of each PAW sample generated was measured. Escherichia coli NCTC 12900 was used throughout the study, whilst sterile distilled water was used as a control. Bacterial enumeration was performed on planktonic E. coli cells exposed to freshly prepared PAW for 0, 10, 20, 30, 40, 50, and 60 minutes. Biofilm evaluation was then carried out, with biofilm formation taking place on polystyrene surfaces. After the formation of wet and dry biofilms, these were exposed to PAW for 0, 5, 10, 15 and 20 minutes. Biofilm detachment was achieved by cell scraping. Results: The results obtained showed approximately a 5 log CFU/mL reduction of planktonic cells after being exposed to PAW for a total of 60 minutes. With regards to dry biofilm formation, the counts for both the PAW exposure and the control were consistently below the detection limit. On the contrary, for the wet biofilms, following 20 minutes of exposure to PAW, there was a 2.5 log CFU/cm2 reduction. Conclusion: This study indicates that PAW can be an effective disinfectant, however, its efficacy is compromised when studying biofilm forms. Furthermore, additional research is needed to establish whether PAW can be utilised by the food industries as a disinfectant, given that some of its components might exert toxic effects. Description: B.Sc. (Hons)(Melit.) 2023-01-01T00:00:00Z