Thesis (M.S.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 63-65).

Thesis (M. Sc.)--University of Hong Kong, 2006.

No description available.

M.Tech. / A variety of fungal species belonging to the genera Aspergillus, Penicillium, Fusarium and Alternaria, Cladosporium are common contaminants of food commodities such as grains, cereals, seeds, nuts, and fruits. These fungal species in turn produce mycotoxins under favourable conditions as secondary metabolites, which have been recorded to have harmful effects in both animals and man. The concern for mycotoxin contamination of food commodities grown and produced in sub-Saharan Africa has grown considerably over the years with increased and improved strategies on mycotoxin monitoring. The aim of this project was to determine and evaluate the quality of food commodities grown and produced in selected rural areas of the southern part of Nigeria in relation to fungi and mycotoxins, evaluate the health implications of the mycotoxins, as well as, suggest possible solutions to reduce exposure of the population in these areas to fungi and mycotoxins in the food. This study was of much importance as the populace of these areas depend solely on the food commodities grown and produced in these areas. Ochratoxin A, aflatoxins, deoxynivalenol, fumonisins and zearalenone are major mycotoxins occurring naturally in most food commodities that have important health significances and as such, it was important to determine the exposure of people in this part of the country to these major mycotoxins. A total of 144 samples comprising of rice (41), maize (39), cocoa (39) and cocoa-based powder beverage (25) collected from the fields, markets and stores were screened for Aspergillus, Fusarium and Penicillium species producing mycotoxins using conventional methods and DNA sequencing which were preceded by serial dilution of samples on agar plates. Further analysis for mycotoxin extraction was done using multi-mycotoxin extraction, strong anion exchange columns and immunoaffinity columns, which was followed by identification and quantification via thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Mycological screening of samples showed incidences of various species of filamentous fungi including A. flavus, A. parasiticus, A. ochraceus, A. niger, F. verticillioides, F. proliferatum and F. graminearum, with highest incidences of A. flavus in rice (65.9%), F. verticillioides in maize (76.9%), A. flavus in cocoa (77.8%) and Cladosporium in cocoa-based powder beverages (32%). Mycotoxicological analysis showed occurrences of aflatoxins, ochratoxin A, zearalenone, fumonisins and deoxynivalenol in all food samples analysed with fumonisins, aflatoxins, ochratoxin A and deoxynivalenol prevalent in maize samples; ochratoxin A, aflatoxins and fumonisisn prevalent in rice samples; aflatoxins, ochratoxin A and fumonisins prevalent in cocoa samples and ochratoxin A, fumonisins and zearalenone prevalent in cocoa-based powder beverage samples. Levels of mycotoxin contamination varied from field to market place to storage with higher contamination of mycotoxins in samples from markets and store houses. In order to determine the health implications of the extracted mycotoxins, cytotoxicity analysis was done using MTT (methylthiozol tetrazolium)- assay on human blood lymphocytes and results showed a reduction in cell viabilities on cells exposed to extracts contaminated with mycotoxins at varying concentrations over 24hrs and 48hrs duration. It was seen that although levels of mycotoxins in samples were below and some above the set regulatory limits of mycotoxins in food, daily exposure to these mycotoxins over a long period of time could be dangerous health-wise influencing symptoms such as immunosuppression, kidney disorders, reproductive health disorders, liver and oesophageal cancers. It is therefore necessary to educate rural population and other populace on the health implications of ingesting these mycotoxins as well as teach them simple and cheap methods of preventing mycotoxin contamination of food commodities.

No description available.

Digitized by Kansas State University Libraries

M.Tech. / A study to determine the occurrence of fungi and their mycotoxins in rural food and their effect on human health was carried out at N’wamitwa (Tzaneen), a rural area of Limpopo province (South Africa). Fifty-eight maize and twenty-nine bambara nuts samples were collected from selected house holds and taken to the storage facilities of the Food, Environment and Health research group (FEHRG) laboratory at the University of Johannesburg for analysis. The samples were analysed for moisture content, fungal infestation, mycotoxin contamination and their toxicity. The moisture content of the samples were at a range of 3-20% moisture. Fungi which included species of the genus Aspergillus, Fusarium and Penicillium were detected at all moisture ranges but more dominant in samples with higher moisture levels. Fungi in this study were able to produce mycotoxins which included deoxynivalenol (DON), zearelenone (ZEA), aflatoxins (AFs), T2- toxin, fumonisins (FBs), ochratoxin A (OTA) and citrinin. The most dominant toxins in maize samples quantified by VICAM were AFs followed by DON, FBs and lastly ZEA and in bambara nuts were FBs followed by DON, AFs and ZEA. HPLC was able to detect higher concentrations of FBs than VICAM. The toxins were then tested for their toxicity using human lymphocytes and the most toxic was DON followed by AFs, FBs and lastly ZEA. Three vials of the same toxin with different concentrations, one with the highest and others with the middle and the lowest concentrations were used to treat the human lymphocytes.

Mycotoxins are secondary metabolites of fungi, which may contaminate animal feed and human food at all stages of the food chain. This has become a global concern and considered an important risk factor mostly for human and animal health. The aim of this project was to elucidate the general health and productivity of domesticated animals in selected rural areas of the Limpopo Province in relation to fungi and mycotoxin and find out possible solutions to avoid in the future further exposure and to improve animal production in rural areas. A total of 95 animal fresh faeces (50 from Mapate and 45 from Nwanedi districts), 50 feed samples (24 from Mapate and 26 from Nwanedi) and 50 fresh milk samples from cattle and goats were screened for fungi and mycotoxin contamination. The multi mycotoxin extraction method was used, followed by thin layer chromatography, also the VICAM immunoaffinity clean up, high performance liquid chromatography, gas chromatography mass spectrophotometry and the ELIZA enzyme linked kit method were used for further mycotoxin determination and quantification. The results obtained from this study revealed that species of Aspergillus, Fusarium and Penicillium fungi contaminated both feed and animal faeces samples. The species Aspergillus niger, A. clavatus, A. flavus, A. fumigatus, Fusarium verticillioides, F. graminerium and F. proliferatum were the most prevalent fungi. Fumonisin B1 and B2, aflatoxins B1, zearalenone and deoxynivalenol (DON) were found in animal feed. Fumonisins B1 and B2 were also found in faecal samples which indicated animal exposure to these mycotoxins. Cattle were the most exposed as compared to goats and pigs. In addition, aflatoxin M1 and traces of fumonisin B1 was detected in cattle and goats milk samples collected from both Mapate and Nwanedi districts. Late harvesting and poor handling of crops during storage seemed to be the reason for the results indicating feed contamination with high levels of fungi and mycotoxins. Daily exposure to this contaminants may influence or/and induce several symptoms such as dermatosis, immunosupression, liver and oesophageal cancer in both animal and human being. There is an urgent necessity to teach rural populations simple and cheap methods of crops storage and techniques to prevent feed and food contamination. / Prof. Mike F. Dutton Mr. F. Eric Van-Zyl

by Wong Siu Kay. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 172-175). / Chapter PARTI : --- Naphthalene contamination in Milk Drinks / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 : --- Methods of determination of Naphthalene in Milk and Packaging Materials --- p.6 / Chapter Chapter 3 : --- Prediction Method I - Simulation --- p.15 / Chapter Chapter 4 : --- Prediction Method II- Mathematical Modelling --- p.24 / Chapter Chapter 5 : --- Atmospheric Effect I - Naphthalene Vapour in Air --- p.31 / Chapter Chapter 6 : --- Atmospheric Effect II- Aromatic Hydrocarbons in Air --- p.44 / Chapter Chapter 7 : --- Naphthalene Contamination In Solid Foods --- p.58 / Chapter Chapter 8 : --- Migration of Naphthalene in other Types of Polymers --- p.69 / Chapter Chapter 9 : --- Further Studies --- p.76 / Reference --- p.31 / Appendix I --- p.88 / Chapter Part II : --- General Study of Plasticisers Migration into Food / Chapter Chapter 1 : --- Introduction --- p.91 / Chapter Chapter 2 : --- Survey of Plasticisers Level in Food Contact Materials --- p.100 / Chapter Chapter 3 : --- Survey of Plasticisers Level in Foodstuff --- p.119 / Chapter Chapter 4 : --- Mathematical Modelling --- p.139 / Chapter Chapter 5 : --- Effect of Microwave Heating --- p.159 / Reference --- p.172 / Appendix II --- p.176

by Wai Yin Karen Fong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves [106]-[110]). / Abstract --- p.2 / Acknowledgments --- p.3 / Dedication --- p.4 / Abbreviations --- p.5 / Table of Contents --- p.7 / Chapter Chapter 1: --- Introduction --- p.11 / Chapter 1.1 --- Overviews of packaging materials --- p.11 / Chapter 1.2 --- Source of contamination --- p.14 / Chapter 1.2.1 --- Contamination from packaging materials --- p.15 / Chapter 1.2.2 --- Contamination of plasticisers from packaging materials and its effect --- p.16 / Chapter 1.3 --- Classification of commercial plasticisers --- p.19 / Chapter 1.3.1 --- Application of plasticisers --- p.20 / Chapter 1.4 --- Analysis of the plasticisers in the food packaging films --- p.22 / Chapter 1.5 --- Analysis of plasticisers in food using isotope dilution technique --- p.22 / Chapter Chapter 2 --- : Instrumentation and Analytical methods --- p.25 / Chapter 2.0 --- Instrumentation --- p.25 / Chapter 2.1 --- Gas chromatography --- p.25 / Chapter 2.2 --- Detector --- p.26 / Chapter 2.2.1 --- Flame ionisation detector --- p.26 / Chapter 2.2.2 --- Mass spectrometer --- p.27 / Chapter 2.2.2.1 --- Ion trap detector --- p.28 / Chapter 2.2.3 --- Ionisation mode --- p.33 / Chapter 2.2.3.1 --- Electron ionisation (EI) --- p.33 / Chapter 2.2.3.2 --- Chemical ionisation (CI) --- p.34 / Chapter 2.4 --- Analytical methods --- p.36 / Chapter 2.3 --- The use of combined GC/MS in the analysis of plasticisers --- p.36 / Chapter 2.3.1 --- Identification by GC/MS --- p.37 / Chapter 2.3.2 --- Qualitative MS --- p.37 / Chapter 2.3.3 --- Quantitative MS --- p.39 / Chapter 2.3.3.1 --- Isotope dilution technique --- p.40 / Chapter Chapter 3: --- Analysis of plasticisers in food packaging materials --- p.41 / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Experimental and Instrumental --- p.42 / Chapter 3.2.1 --- Reagents --- p.43 / Chapter 3.2.2 --- Materials --- p.43 / Chapter 3.3 --- Identification of food packaging materials --- p.43 / Chapter 3.3.1 --- Fourier transform infrared spectrometry --- p.44 / Chapter 3.3.2 --- Burning test --- p.45 / Chapter 3.3.3 --- Solvent dissolution method --- p.46 / Chapter 3.4 --- Extraction of plasticisers from the packaging materials --- p.49 / Chapter 3.4.1 --- Chloroform extraction --- p.50 / Chapter 3.4.2 --- Solvent reflux method --- p.50 / Chapter 3.5 --- Results and discussion --- p.51 / Chapter 3.5.1 --- Precision test --- p.51 / Chapter 3.5.2 --- Calibration curve --- p.52 / Chapter 3.5.3 --- Detection limit --- p.54 / Chapter 3.5.4 --- Recovery --- p.54 / Chapter 3.6 --- Survey of the level of plasticisers in food packaging materials --- p.55 / Chapter 3.7 --- Conclusion --- p.66 / Chapter 4.0 --- Analysis of plasticisers in foods --- p.67 / Chapter 4.1 --- Introduction --- p.67 / Chapter 4.2 --- Experimental and instrument --- p.67 / Chapter 4.2.1 --- Reagents --- p.68 / Chapter 4.2.2 --- Materials --- p.68 / Chapter 4.3 --- Analysis --- p.69 / Chapter 4.3.1 --- selection of stable isotope labelled analogues --- p.69 / Chapter 4.3.2 --- Synthesis of deuterated internal standard --- p.70 / Chapter 4.4 --- Extraction of foods --- p.71 / Chapter 4.4.1 --- Clean up method --- p.73 / Chapter 4.4.2 --- Quantitation --- p.77 / Chapter 4.5 --- Results and discussion --- p.82 / Chapter 4.5.1 --- Precision test --- p.82 / Chapter 4.5.2 --- Calibration curve --- p.84 / Chapter 4.5.3 --- Detection limit --- p.85 / Chapter 4.5.4 --- Survey of the level of plasticisers in food --- p.86 / Chapter 4.6 --- Conclusion --- p.91 / Chapter 5.0 --- Analysis of plasticisers in food by EI and CI method / Chapter 5.1 --- Introduction --- p.93 / Chapter 5.2 --- Experimental and Instrumental --- p.94 / Chapter 5.2.1 --- Reagents --- p.95 / Chapter 5.2.2 --- Materials --- p.95 / Chapter 5.3 --- Extraction of foods --- p.95 / Chapter 5.3.1 --- Clean up method --- p.95 / Chapter 5.4 --- Result and discussion --- p.95 / Chapter 5.4.1 --- Precision test --- p.95 / Chapter 5.4.2 --- Calibration curve --- p.97 / Chapter 5.4.3 --- Detection limit --- p.99 / Chapter 5.4.4 --- Survey of plasticisers in food by EI and CI method --- p.100 / Chapter 5.4.5 --- Paired t-Test --- p.103 / Chapter 5.5 --- Conclusion --- p.104 / Chapter Chapter 6 --- Conclusion --- p.105 / Bibliography --- p.106 / Appendices : / Chapter 1 --- The mass spectrum of DEP --- p.i / Chapter 2 --- The mass spectrum of DIBA --- p.i / Chapter 3 --- The mass spectrum of DIBP --- p.ii / Chapter 4 --- The mass spectrum of DBP --- p.ii / Chapter 5 --- The mass spectrum of DBS --- p.iii / Chapter 6 --- The mass spectrum of ATBC --- p.iii / Chapter 7 --- The mass spectrum of BBP --- p.iv / Chapter 8 --- The mass spectrum of DEHA --- p.iv / Chapter 9 --- The mass spectrum of DPOP --- p.v / Chapter 10 --- The mass spectrum of DEHP --- p.v / Chapter 11 --- The mass spectrum of DCHP --- p.vi / Chapter 12 --- The mass spectrum of DOAZ --- p.vi / Chapter 13 --- The mass spectrum of DOS --- p.vii / Chapter 14 --- Calibration curve of GC/FID --- p.viii / Chapter 15 --- Calibration curve of GC/MS (magnum) --- p.xi / Chapter 16 --- Calibration curve of GC/MS (GCQ) --- p.xiv