Location: National Peanut Research LaboratoryTitle: Aspergillus and aflatoxin in groundnuts (Arachis hypogaea L.) and groundnut cake in Eastern Ethiopia Author
|Arias De Ares, Renee|
Submitted to: Journal of Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2016
Publication Date: 9/22/2016
Citation: Mohammed, A., Alemayehu, C., Dejene, M., Hoisington, D.A., Sobolev, V., Arias De Ares, R.S., Fininsa, C. 2016. Aspergillus and aflatoxin in groundnuts (Arachis hypogaea L.) and groundnut cake in Eastern Ethiopia. Journal of Food Additives & Contaminants. 9(4):4290-298. doi:10.1080/19393210.2016.1216468. Interpretive Summary: In order to create awareness of the presence of aflatoxin contamination in peanut and peanut products, a survey and aflatoxin analysis of seeds and peanut cake was performed in four districts in eastern Ethiopia during two harvest seasons. Presence of aflatoxin contamination and incidence of Aspergillus species, some of them known to produce aflatoxin were recorded. A total of 22 and 41% of seed samples showed aflatoxin contamination in 2013/2014 and 2014/2015, respectively; whereas 68% of the peanut cake samples had some level of aflatoxin. In both cases, those levels reached values above the limits considered acceptable for human consumption.
Technical Abstract: Groundnut (Arachis hypogaea L.) is an important cash and food crop in eastern Ethiopia. The lack of awareness and data on Aspergillus and aflatoxin contamination of groundnut and groundnut food products in the area are lacking. Therefore, this study was conducted to: i) assess major Aspergillus species and aflatoxin contamination associated with groundnut seeds and “Halawa”( local cake) across different agro-ecological zones in eastern Ethiopia, and ii) evaluate growers’ management practices that can promote fungal contamination. A total of 160 groundnut seed samples were collected from farmers’ stores during 2013/14 and 2014/15 harvest seasons. Additionally 50 groundnut cakes collected from open market cafe and restaurants were also included in the study. Fungal isolation was performed from seed samples, and the Aspergillus spp. recorded for both cropping seasons. The identified species were: A. flavus, including L and S-strains, A. parasiticus, A. niger, A .tamarii, A. caelatus, and A. ochraceus. Aspergillus flavus was the most abundant species followed by A. parasiticus in both seasons. Aflatoxin analyses of seed samples were performed using UPLC; 22 and 41 % samples from 2013/14 and 2014/15 harvests, respectively, were positive. Among contaminated samples, total aflatoxin (B1, B2, G1, G2) concentrations of 786 and 3135 ng•g-1 from 2013/14 and 2014/15 samples, were recorded. The level of aflatoxin concentration in seed samples varied from 0.06 to 2526 ng•g-1 of aflatoxins B2 and B1, respectively. In infected seed samples aflatoxin B1 was the most abundant followed by G1 in both seasons. Analysis of groundnut cake “Halawa” showed that 68 % of the samples were contaminated with aflatoxins, the majority with concentrations below 20 ng•g-1, though one sample reached 158 ng•g-1 of aflatoxin B1. The present study revealed high levels and frequency of aflatoxin contamination of groundnut seeds and cakes in East Ethiopia, in many cases the levels were significantly higher than the maximal legislated for human consumption in all the countries.