SURVEY ON FUNGAL AND AFLATOXIN CONTAMINATION OF STORED MAIZE (Zea mays) GRAINS IN SOUTHERN ETHIOPIA

Abstract

Maize (Zea mays L.) is attacked by more than sixty diseases and a number of species of insect pests and microorganisms in the field as well as in the storage. Fungi are among the principal causes of deterioration and yield loss on farmers’ maize during the storage period. Among the storage fungal pathogens Fusarium, Aspergillus, and Penicillium are the most predominant species attacked maize grain and resulting in production of harmful products of Mycotoxins. The study was conducted at the Hawassa University College of Agriculture in plant pathology laboratory. The study was aimed to study effect of storage duration and storage type on fungal contamination and assessments of aflatoxin contamination of maize grains in southern Ethiopia . A total of 165 Maize grains samples were collected from different storage type and storage duration in southern Ethiopia, in 2019/2020. A total of seven fungal genera consisting of twenty one species of fungi were isolated from maize grain by using morphological characterstics; Fusarium spp. were most frequently isolated, followed by Aspergillus spp.The fungal contaminations of maize grains were significantly different (p<0.05) increased with storage periods. At the last six months of storage, the contamination of the Fungal isolates revealed that Fusarium spp had the highest contamination of 43.6% followed by Aspergillus spp, 28.6%, then Penicillium spp 5.27%, Alternaria spp 4.12%, Rhizopus spp 3.08%,Tricoderma spp 1.65% while the least contamination of 1.22%, was Cladosporium spp. The highest contamination of Fusarium spp (44.79%) and Aspergillus spp (24.98) were recorded in storage basket whereas the minimum contamination of Fusarium spp (35 %) and Aspergillus spp (15.5%) were obtained from plastic storage. As a result of this research, the Plastic container storage was determined to be more appropriate for protecting the stored maize grains from fungal attack during the storage periods and the stored grains have low fungal contamination until initial t o six months. Therefore, storage Basket, storage Crips, storage Sacks and Gombisa storages were inadequate for protecting stored maize from fungal attacks. Total aflatoxins has quantified from the maize samples collected from different maize growing areas in southern Ethiopia by using Enzyme Linked Immune Assay (ELISA) Kit. The result reveal that the mean 32(66.7%) of 48 maize grain sample were positive for aflatoxin contamination with levels of aflatoxin concentration ranging from 0.21-18.06µg/kg. The average aflatoxin concentrations detected in the present study were below the US Food and Drug Administration (FDA), the World Health Organization (WHO) maximum limit of total aflatoxin 20μg/kg. The EU has maximum limit of 4 μg kg−1 total aflatoxin in cereal for direct human consumption. Thus, most of the samples contaminated with aflatoxins in this study are not suitable for human consumption by the EU standards.