New hepatocarcinogen, fumonisins : food contamination and the distribution of fumonishin-producing fungi

采用高效液相色谱法研究了日本、尼泊尔、中国、泰国和马来西亚玉米及玉米制品中天然存在的福马菌素B1和B2（一种肝癌发生的启动子）。在9份进口玉米粒和6份面筋饲料样品中，8份玉米（0.6 ~ 4.1马克杯/g）和所有面筋饲料（0.3 ~ 2.4马克杯/g）样品中检出伏马菌素B1，同一份玉米（0.3 ~ 10.2马克杯/g）和3份面筋饲料（0.8 ~ 8.5马克杯/g）样品中检出伏马菌素B2。ELISA分析还发现2个玉米和所有面筋饲料样品中含有黄曲霉毒素B1和伏马菌素。17份玉米粉样品中，14份和5份样品被伏马菌素B1和B2污染，最高水平分别为2.6和2.8马克/克。至于在日本销售的以玉米为原料的食品，没有发现明显的伏马菌素污染。在尼泊尔的24份玉米粒样品中，伏马毒素B1和B2阳性12份和7份，平均分别为0.6和1.6马克/克。同一样品的最大含量分别为4.6和5.5马克杯/克。在中国上海和北京收获的玉米样品中，检测到不同浓度的伏马菌素B1和B2。泰国样本对伏马菌素B1和B2呈阳性反应，水平分别为0.3至1.8和0.1至0.4马克/克。在马来西亚，一些样本呈伏马菌素B1和B2阳性。真菌学调查显示，在日本的农田中存在产生伏马菌素的真菌。这些发现首次证明了亚洲国家玉米和玉米制品中伏马菌素的污染水平很高。在混合饲料原料中也检测到曲霉毒素和黄曲霉毒素B1的天然共存。

Natural occurrence of fumonisin B1 and B2, a promoter for hepatocarci nogenesis, was investigated in corn and corn-based products sampled in Japan, Nepal, China, Thailand and Malaysia by high-performance liquid chromatographic method. In 9 imported corn kernel and 6 gluten feed samples, fumonisin B1 was detected in 8 corn (0.6-4.1 mug/g) and all gluten feed (0.3-2.4 mug/g) samples, while fumonisin B2 was found in the same corn (0.3-10.2 mug/g) and 3 gluten feed (0.8-8.5 mug/g) samples. ELISA analysis also revealed the contamination of aflatoxin B1 in 2 corn and all gluten feed samples along with fumonisins. In 17 samples of corn grits, 14 and 5 samples were contaminated with fumonisin B1 and B2, with the maximum levels of 2.6 and 2.8 mug/g, respectively. As for corn-based foodstuffs marketed in Japan, no significant contamination of fumonisins was observed. Among 24 samples of corn kernels in Nepal, 12 and 7 samples were positive for fumonishin B1 and B2, and averaged to 0.6 and 1.6 mug/g, respectively. The maximal contents were counted to 4.6 and 5.5 mug/g in one same sample respectively. In corn samples harvested at Shanghai and Beijing in China, fumonisin B1 and B2 were detected in various concentrations. Thailand samples were positive for fumonisin B1 and B2 at levels ranging from 0.3 to 1.8 and 0.1 to 0.4 mug/g, respectively. In Malaysia, a few samples were positive for fumonisin B1 and B2. Mycological survey has revealed the presence of fumonisin-producing fungus in a crop field in Japan. These findings have firstly demonstrated the contamination of fumonisins with high levels in corn and corn-based products in Asian contries. Natural co-occurrence of fumonisins and aflatoxin B1 was also detected in raw materials for mixed feed.