Fusarium diversity and mycotoxin occurrence in proso millet in Korea

Abstract

The incidence and toxicological characteristics of mycotoxigenic Fusarium were assessed in 24 proso millet samples collected from fields on Jeju Island, Korea. Fusarium isolates from the millet samples comprised of F. asiaticum (19.5%), F. acuminatum (12.4%), F. graminearum (11.8%), F. incarnatum (10.7%), F. equiseti (10.7%), F. tricinctum (8.9%), and 12 other Fusarium species. The millet samples were contaminated with zearalenone (62.5%), deoxynivalenol (45.8%), and nivalenol (41.7%) at maximum levels of 117.7, 861.8, and 433.2 ng/g, respectively. The T-2/HT-2 toxins were also detected. Co-occurrence of more than two mycotoxins was observed in 58.3% (14/24) of the samples. The results of an in vitro assay of mycotoxin production revealed that 19 of 22 Fusarium isolates produced at least one mycotoxin in rice medium. The isolates of F. asiaticum, F. graminearum, F. kyushuense, F. incarnatum, and F. equiseti produced DON, NIV, and ZEN. Two F. fujikuroi isolates produced high levels of FBs (3777–12,424 μg/g, sum of B1 and B2). The isolates of F. tricinctum, F. acuminatum, F. incarnatum, and F. equiseti produced T-2/HT-2 toxins at up to 13.48 μg/g. These findings demonstrate that the major Fusarium species found in Korean proso millet are mycotoxigenic, thus further monitoring is necessary.