Table_4_Aflatoxin contamination of maize and groundnut in Burundi: Distribution of contamination, identification of causal agents and potential biocontrol genotypes of Aspergillus flavus.pdf

Aflatoxin contamination of the staples maize and groundnut is a concern for health and economic impacts across sub-Saharan Africa. The current study (i) determined aflatoxin levels in maize and groundnut collected at harvest in Burundi, (ii) characterized populations of Aspergillus section Flavi associated with the two crops, and (iii) assessed aflatoxin-producing potentials among the recovered fungi. A total of 120 groundnut and 380 maize samples were collected at harvest from eight and 16 provinces, respectively. Most of the groundnut (93%) and maize (87%) contained aflatoxin below the European Union threshold, 4 μg/kg. Morphological characterization of the recovered Aspergillus section Flavi fungi revealed that the L-morphotype of A. flavus was the predominant species. Aflatoxin production potentials of the L-morphotype isolates were evaluated in maize fermentations. Some isolates produced over 137,000 μg/kg aflatoxin B1. Thus, despite the relatively low aflatoxin levels at harvest, the association of both crops with highly toxigenic fungi poses significant risk of post-harvest aflatoxin contamination and suggests measures to mitigate aflatoxin contamination in Burundi should be developed. Over 55% of the L-morphotype A. flavus did not produce aflatoxins. These atoxigenic L-morphotype fungi were characterized using molecular markers. Several atoxigenic genotypes were detected across the country and could be used as biocontrol agents. The results from the current study hold promise for developing aflatoxin management strategies centered on biocontrol for use in Burundi to reduce aflatoxin contamination throughout the value chain.

黄曲霉毒素对主食玉米和大豆的污染，对撒哈拉以南非洲地区的健康和经济影响构成了担忧。本研究（i）确定了在布隆迪收获时采集的玉米和大豆中的黄曲霉毒素水平，（ii）对与两种作物相关的曲霉属 Flavi 部的种群进行了鉴定，（iii）评估了从回收的真菌中产生的黄曲霉毒素潜力。共收集了120个花生和380个玉米样本，分别来自8个和16个省份。大部分花生（93%）和玉米（87%）中的黄曲霉毒素含量低于欧盟的阈值，即每千克4微克。对回收的曲霉属 Flavi 真菌的形态学特征进行分析，发现柠檬酸型 A. flavus 是优势物种。对柠檬酸型分离株的黄曲霉毒素产生潜力在玉米发酵过程中进行了评估。一些分离株产生了超过137,000微克/千克的黄曲霉毒素B1。因此，尽管收获时的黄曲霉毒素水平相对较低，但两种作物与高毒性真菌的关联仍存在显著的产后黄曲霉毒素污染风险，并暗示了在布隆迪减轻黄曲霉毒素污染的措施应当得到开发。超过55%的柠檬酸型 A. flavus 不产生黄曲霉毒素。这些非产毒的柠檬酸型真菌通过分子标记进行了鉴定。在全国范围内检测到多种非产毒基因型，可被用作生物控制剂。当前研究的成果为在布隆迪开发以生物控制为中心的黄曲霉毒素管理策略提供了希望，旨在整个价值链中降低黄曲霉毒素的污染。