Occurrence of aflatoxigenic fungi and aflatoxins in maize grains and associated awareness and handling practices among farmers and traders in South Sudan

Abstract

Maize is a popular staple food among the urban population of South Sudan. However, due to inadequate food safety surveillance and enforcement systems, there is limited information on the aflatoxin safety of maize grains at farm and market levels. Therefore, this study aimed at assessing aflatoxins awareness and handling practices of maize grains among randomly selected farmers (n=30) and traders (n=30) as well as determining the moisture content, Aspergillus species counts and aflatoxins contamination. A cross-sectional descriptive study was carried out in Magwi maize producing areas, Juba retail/wholesale markets and Nimule border points of South Sudan. Moisture content, fungal and aflatoxins contamination in maize grain samples were determined using dry air oven method, dilution plating technique, and High-Performance Liquid Chromatography (HPLC), respectively. The respondent results showed that farmers (97%) and traders (83%) were unaware of aflatoxins. About 83% of the farmers dried their maize grains on tarpaulins, for 4 - 5 days (77%). In addition, most farmers (77%) stored their maize grain bags on raised platforms, whereas most traders (73%) stored grains on bare ground. All the maize grains met the required moisture content limit (below 13.5%). Maize from Nimule main park had the highest levels of contamination with Aspergillus flavus (9 log CFU/g), Aspergillus parasiticus (12 log CFU/g), aflatoxin B₁ (505.56 μg/kg) and total aflatoxins (1,032.19 μg/kg). Maize from Gudele market was contaminated with Aspergillus parasiticus (12 log CFU/g), and aflatoxin B₁ (76.55 μg/kg), and had a total aflatoxin content of 94.09 μg/kg. Omeo farmers’ maize grains had the least levels of contamination of Aspergillus parasiticus (6 log CFU/g), aflatoxin B₁ (4.39 μg/kg), and total aflatoxins (7.83 μg/kg). In addition, Aspergillus flavus was not detected from Omeo farmers’ maize grains and no aflatoxins were detected from Agoro and Paluonganyi farmers’ grains. This study recommends wider aflatoxins awareness and regular aflatoxin screening of maize grains by the relevant stakeholders in South Sudan.