Applied Mycology Group, Cranfield Health, Cranfield University, Cranfield, Bedford, MK43 0AL, UK.
Mycotoxin Res. 2013 Nov;29(4):209-19. doi: 10.1007/s12550-013-0176-9. Epub 2013 Aug 17.
Samples of stored maize from villages located in five different agroecological zones (southern lowlands, northern lowlands, Senqu river valley, foothills and mountains) of Lesotho were collected in 2009/10 and 2010/11 and assessed for contamination with toxigenic fungi. The water activity of all samples collected during the two seasons was <0.70. The total fungal populations of the maize from different regions in the two seasons was not significantly different (p > 0.05). Fusarium verticillioides, F. proliferatum and F. subglutinans predominated in different regions in both seasons based on molecular analyses. In the 2009/10 season, the isolates of these species all produced FB1, while in the 2010/11 season, very few produced FB1. A. flavus isolates (2009/10) were recovered from mountains and Senqu river valley samples while the 2010/11 isolates were predominantly from the foothills and northern lowlands. The mountain isolates of Aspergillus section Flavi produced the highest levels of AFB1 (20 mg kg(-1)). Aspergillus parasiticus was only isolated from the foothills, Senqu river valley and southern lowlands samples, and the AFB1 levels produced ranged from 'none detected' to 3.5 mg kg(-1). The Aspergillus ochraceous isolates were least frequently encountered in both seasons. In the 2009/10 season, the isolates from the northern lowlands produced ochratoxin A (OTA) in culture. No isolates of A. niger from different regions in both seasons produced any OTA. Multi-mycotoxin analyses of the maize samples were done for a range of mycotoxins. At least one sample from each region in both seasons was FB1-positive. FB1 levels for 2010/11 samples (7-936 μg kg(-1)) were higher than in the 2009/10 season (2-3 μg kg(-1)). In both seasons, the mountains registered the highest levels of FB1. Deoxynivalenol (DON) was recovered from all the samples analysed, with the highest mean contamination of 1,469 μg kg(-1) in samples from the northern lowlands. Moniliformin (MON) was detected from all agroecological zones in the two seasons (5-320 μg kg(-1) in 2009/10; 15-1,205 μg kg(-1) in 2010/11). Emerging toxins such as fusaproliferin (FUS) and beauvericin (BEA) were also detected. OTA was not detected in any of the samples analysed. Only one 2009/10 sample in the Senqu river valley was positive for AFB1. This is the first report on toxigenic fungi and multi-mycotoxin contamination of maize samples from subsistence farmers' stores in different agroecological zones of Lesotho.
2009/10 年和 2010/11 年，从莱索托五个不同农业生态区（南部低地、北部低地、森奎河谷、丘陵和山区）的村庄收集了储存的玉米样本，并评估了其对产毒真菌的污染情况。两个季节收集的所有样本的水活度均<0.70。两个季节不同地区玉米的总真菌种群没有显著差异（p>0.05）。基于分子分析，在两个季节的不同地区，均以镰孢菌属 verticillioides、F. proliferatum 和 F. subglutinans 为主。在 2009/10 季节，这些物种的分离株均产生 FB1，而在 2010/11 季节，很少产生 FB1。在 2009/10 季节，从山区和森奎河谷样本中回收了黄曲霉属 A. flavus 分离株，而 2010/11 季节的分离株主要来自丘陵和北部低地。山区的黄曲霉属节段 Flavi 产生的 AFB1 水平最高（20mgkg(-1)）。仅从丘陵、森奎河谷和南部低地样本中分离出寄生曲霉属 A. parasiticus，产生的 AFB1 水平范围为“未检出”至 3.5mgkg(-1)。在两个季节中，赭曲霉属的分离株最不常见。在 2009/10 季节，来自北部低地的分离株在培养中产生了赭曲霉毒素 A（OTA）。两个季节不同地区的黑曲霉属 niger 分离株均未产生任何 OTA。对玉米样本进行了多种霉菌毒素的分析。两个季节的每个地区至少有一个样本呈 FB1 阳性。2010/11 样本的 FB1 水平（7-936μgkg(-1))高于 2009/10 季节（2-3μgkg(-1))。在两个季节中，山区的 FB1 水平最高。在所分析的所有样本中均回收了脱氧雪腐镰刀菌烯醇（DON），北部低地样本的平均污染水平最高，为 1469μgkg(-1)。在两个季节中，均从所有农业生态区检测到单端孢霉烯族毒素（MON）（2009/10 年为 5-320μgkg(-1)；2010/11 年为 15-1205μgkg(-1)）。还检测到新兴毒素如呋甾醇（FUS）和布草霉素（BEA）。在分析的任何样本中均未检测到 OTA。在森奎河谷的一个 2009/10 样本中仅检测到 AFB1 呈阳性。这是首次报道莱索托不同农业生态区自给农民储存玉米样本中产毒真菌和多种霉菌毒素的污染情况。
