Aspergillus Species and Aflatoxin Contamination of Pre and Post-Harvest Maize in West Gojam Ethiopia.
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Date
2015-06
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Addis Ababa University
Abstract
Maize is an important crop for overall food security and for economic development in Ethiopia. However, the grain is vulnerable to degradation by mycotoxigenic fungi which include Aspergillus, Fusarium and Penicillium. Aflatoxins, a group of mycotoxins mainly produced by Aspergillus flavus and Aspergillus Parasiticus, have adverse health effects on humans and livestock that ingest aflatoxin contaminated food products and feeds. Therefore, the present study was designed to assess the level of Aspergillus species and Aflatoxin contamination in pre and post-harvest maize from West Gojam. A study was carried out from September 1, 2014 to May 1 2015. Pre-validated structured questionnaire was used to obtain information on maize production practices. Aspergillus species were isolated from Maize kernels on potato dextrose agar medium. Aflatoxin contaminations in Maize kernels were analyzed by High Performance liquid chromatography fluorescence detector. The results indicated that from fifteen pre- and fifteen post-harvest maize samples 77.7 % of pre harvest with level range from 3.13 to 63.66 μg/kg and 80 % of post-harvest sample with level range from 9.02 to 139.8 μg/kg were contaminated by total aflatoxin. The mean total aflatoxin was 18.38 μg/kg for pre harvest and 43.36μg/kg for post-harvest. Average aflatoxin concentrations in the samples were (AFG2= 2.10 μg/kg, AFG1= 10.10 μg/kg and AFB2= 1.17μg/kg) in pre harvest sample and (AFG2= 8.14 μg/kg, AFG1= 18.11 μg/kg and AFB2= 7.2 μg/kg) in post-harvest sample. In addition, the pre and post maize sample was also showed that high mean aflatoxin B1 level of 5.00 μg/k with 66.7% in pre harvest maize and 9.86 μg/kg with 87.7% in post-harvest maize. To be precise, Paired t-test statistical analysis for mean of total and aflatoxin B1 in pre and post- harvest maize samples was showed that both total and aflatoxin B 1 increased significantly from pre harvest to post - harvest maize (p< 0.05). 33.3 % of pre harvest and 73.3 % of post-harvest maize samples were exceeded the US Food and Drug Administration and the World Health Organization (tolerance limit of 20μg/kg). About 66.7 % pre harvest and 86.7% post-harvest of this study sample were exceeded the acceptance limit of total Aflatoxin recommended by European Union maximum limit (4 μg/kg). About 66.7 % pre harvest and 86.7% post-harvest of this study sample were exceeded the acceptance limit of Aflatoxin B1 recommended maximum limit (2 μg/kg) of European Union. This research has also shown that high Aspergillus species contamination in pre and post-harvest maize, in pre harvest 53.3 % of s maize samples were contaminated by Aspergillus species (26.7% = A.flavus, 13.3%= A. parasiticus and 13.3%= A. niger) and in post-harvest X
79.9% of maize samples were contaminated by Aspergillus species (46.6 % = A.flavus, 20.0 %= A. parasiticus and 13.3%= A. niger) species. In conclusion, the results of the present study revealed that although it was expected that pre harvest maize to have minimal Aspergillus and aflatoxin contamination, the contamination was high in pre harvest and significantly increase from pre harvest to post harvest. Therefore, prevention through pre, harvest and postharvest control management practice should be done to ensuring a safe final product.
Key words: Mycotoxin; Aspergillus species; Aflatoxin, pre and post- harvest; Maize
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Keywords
Mycotoxin; Aspergillus species; Aflatoxin, pre and post- harvest; Maize