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dc.contributor.advisorDr. Abdulaziz Adishen_US
dc.contributor.advisorProf. Sarah De Saegeren_US
dc.contributor.advisorDr. Ashagrie Zewduen_US
dc.contributor.authorAyelign, Abebe-
dc.descriptionSubmitted for the Fulfillment of Requirements for the Degree of Doctor of Philosophy in Food Science and Nutritionen_US
dc.description.abstractWith 40% of children five years and under being stunted (CSA, 2014), Ethiopia has one of the highest rates of under nutrition in Sub-Saharan Africa. Growth faltering reaches its peak, during the period when complementary foods (CFs) are often introduced, indicating that inappropriate introduction and patterns of complementary feeding may contribute to the problem. Interventions have been designed to improve the quality of CFs, but these have paid little attention to the potential contamination with aflatoxin and microbial pathogens. Therefore, this study intended to assess the knowledge and practices of the mothers/caregivers on issues related to aflatoxin in CFs, investigate the safety of CFs in terms of microbial and aflatoxin contamination, assess aflatoxin exposure among young children using urinary biomarkers and develop HACCP based SOPs for the safe preparation of CFs. The knowledge and practice study involved 195 mothers from 20 Districts from Amhara, Tigray, Oromia, and Southern Nations Nationalities and Peoples (SNNP) regions and addressed a range of issues related to aflatoxin in CFs using structured questionnaires. A total of 146 samples collected from 20 Districts were tested for the presence of Cronobacter sakazakii (C. sakazakii), coliforms and Escherichia coli (E. coli); and determined for the levels of total aflatoxin. The incidence of C. sakazakii was detected using ISO/TS 22964:2006 method while coliforms and E. coli were detected using the conventional most probable number (MPN) method. The levels of total aflatoxins were determined using Enzyme linked immunosorbent assay (ELISA). The biomarker study was conducted with 200 urine samples collected from 200 children and assessed for the levels of AFB1, AFB2, AFG1, AFG2 and AFM1 using a validated LCMS/ MS method. The knowledge and practice study results indicate that, 95% (186/195) of the respondents ploughing the land before growing the next crop, 91% (177/195) of them used crop rotation schedule, and 81% (157/195) reported the practice of removing old seed heads, stalks and other debris. A total of 70% (138/195) respondents used the threshing method known as trampling by hoofed animals on a threshing bare floor. Among the respondents, 27% (53/195) of them used ‘Gota’, 28% (54/195) used both ‘Gota’, ‘Gotera’ and polypropylene bags for home storage of cereals and legumes. Only, 7% (14/195) of the respondents used underground pit storage. C. sakazakii was detected in 12% (17/146) of the samples, while 45% (66/146) and 6% (9/146) of the samples collected were positive for coliforms and E. coli, at a level of >1100 CFU/g and 150 CFU/g respectively. Total aflatoxin was detected in19 out of 20 (with mean range of 2.3-88 μg/kg), 62 out of 66 (with mean range of 0.3-9.9 μg/kg), and 59 out of 60 (with mean range of 0.5-12.4 μg/kg) moldy, premilling and CFs samples respectively. The biomarker study also revealed that, aflatoxins were detected in 17% (34/200) of the urine samples whereby four out of five analyzed aflatoxins were detected. AFM1 was detected in 7% (14/200) of the urine samples in a range of 0.06-0.07 ng/mL. AFB2, AFG2 and AFG1 were detected in respectively 4.5% (9/200), 3% (6/200) and 2.5% (5/200) of the urine samples whereas AFB1 was not detected in any of the samples. In this study, there was no correlation between the different malnutrition categories (stunted, wasting and underweight) and aflatoxin exposure. In conclusion, most respondents were unaware of toxic effects of aflatoxins on human and animal health. The identification of more microbial contamination in CFs from post production to following one month storage implies poor hygienic practices or cross-contamination by production equipment. Although aflatoxin levels were considered safe for consumption in most samples, more effort should be implemented to reduce these contamination level, particularly as these CFs are intended for direct consumption by young children. The biomarker analysis showed a clear exposure of young children to aflatoxins. Therefore, message to improve public awareness is important to prevent the health consequences of aflatoxins. Further, implementation of the HACCP based SOPs should be encouraged for preventing the CFs from the risks of aflatoxin and microbial contamination.en_US
dc.description.sponsorshipAddis Ababa Universityen_US
dc.publisherAddis Ababa Universityen_US
dc.subjectComplementary Fooden_US
dc.subjectC. Sakazakiien_US
dc.subjectExposure Assessmenten_US
dc.subjectE. Coli, Grain Banksen_US
dc.titleAflatoxin and Microbial Contamination of Complementary Foods and Exposure Assessment among Young Children Using Urinary Aflatoxin Biomarkers in Ethiopiaen_US
Appears in Collections:Thesis-Food and Nutritional Sciences

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