Study on Aspergillus species and Aflatoxin Levels in Sorghum (sorghum bicolor L.) stored at different period and storage system in Kewet Districts, Northern Shewa, Ethiopia.
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2015-06
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Abstract
Sorghum serves as staple food for over 100 million people in Sub-Saharan African countries. It
is the most important nutritional security crop and ranks third among major cereal crops in
terms of area and production next to teff and maize in Ethiopia. However, sorghum is susceptible
to contamination by fungal species mainly Aspergillui flavus and Aspergillui parasiticus species
producing mycotoxins, aflatoxins that have hepatotoxic and carcinogenic effects on humans and
animal. Study was conducted to assess Aspergillus species and aflatoxin levels in sorghum
(sorghum bicolor L.) stored at different period and storage system. Thirty Samples were
analyzed for aflatoxins contamination using HPLC with fluorescent detection and Aspergillus
species were isolated and identified using culture media. About 56.7%, 16.7%, and 23.3% of the
sorghum samples were found to be contaminated with Aspergillus flavus, Aspergillus niger and
Aspergillus parasiticus, respectively. Total aflatoxin and AFB1 contamination occurred in
sorghum with a maximum concentration range of 11.44 to 344.26μg/kg and 3.95 to 153.72μg/kg,
respectively. The levels of Aflatoxins detected in sorghum were within the range of 1.17 to
91.82μg/kg for AFB2, 3.22 to 52.02μg/kg for AFG2 and 9.87 to 139.64μg/kg for AFG1.
Sorghum stored for ≥ 2 years had high level of the aflatoxin B1 (52.19 μg/kg) followed by
sorghum stored for < 12 months (38.24 μg/kg). Although storage period had resulted in no
significant difference in AFB2, AFG1, and AFG2 concentrations, AFB1 varied significantly
(P<0.05). On the other hand, the concentration of aflatoxins in all sorghum samples surpassed
the maximum level set by the European commission, 10μg/kg for total aflatoxin and 5μg/kg for
aflatoxin B1.Therefore, this situation clearly demands wider national or international programs
for the control of aflatoxin contamination in sorghum. In conclusion, creating unfavorable
conditions for fungal growth with storage system and use of proper storage methods may help in
minimizing aflatoxin contamination.
Keywords: Sorghum; Aflatoxin; Aspergillus spp., Storage
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Keywords
Sorghum; Aflatoxin; Aspergillus spp., Storage