Fusarium and its mycotoxins in durum wheat harvested in Argentina

PALACIOS, S.; RAMIREZ, M.L.; REYNOSO, M.M.; CHULZE, S. N.; FARNOCHI, M.C.; TORRES, A.M.

Mendoza

Conferencia; MYCORED ARGENTINA ISM 2011 ConferenceStrategies to reduce the impact of; 2011

UNRC- European Comisssion Mycored Project. Sociedad Latinoamericana de Micotoxicología

Fusarium species are plant pathogens commonly associated with common and durum wheat. Under favorable environmental conditions, this species can produce several micotoxins. Generally, the Fusarium toxins found in wheat are trichothecenes, such as deoxynivalenol (DON) and nivalenol (NIV). However, there have been some reports of the presence of fumonisins in common wheat and sub-products. The objectives of this study were to evaluate the mycoflora mainly Fusarium species and to determine the presence of Fusarium micotoxins DON, NIV and FB1 in 55 durum wheat samples from 2007 and 2008 harvest seasons in the South of Buenos Aires Province, Argentina. Isolation and identification of Fusarium species was determined and micotoxins analyses were done by HPLC. The presence of fumonisin B1 (FB1) was confirmed by LC/MS/MS.The mycological survey showed that all the samples were contaminated with Fusarium species. The percentage of Fusarium contamination varied between 10 and 60 % and 8 and 66% during 2007 and 2008, respectively. During both harvest seasons, one of the main species isolated was F. proliferatum, in percentages that varied between 7 and 100%. Other species isolated in lower frequency were F. oxysporum, F. subglutinans, F. semitectum,F. poae, F. solani, F. graminearum and F. verticillioides. NIV and DON were detected in 10 and 11 samples from 2008 harvest season, respectively. The levels of NIV ranged from 132 to 752 ìg/kg, while DON levels ranged from 60 to 7,719 ìg/kg. However, only 1 sample exceeded the maximum permitted limit of 1,750.00 ìg/kg set by the European Commission for DON in durum wheat grains. During 2007 harvest season NIV and DON were not detected in the samples. On the other hand, natural fumonisin contamination was found in both years. However, fumonisin levels were higher in the first than in the second year. During 2007, 29 out of 30 samples were positive for fumonisin B1 in levels that ranged from 10.5 to 987.2 ìg/kg. The presence of FB1 was confirmed by LC-MS/MS. In the second year (2008) none of the 25 samples analyzed showed fumonisin contamination by HPLC-FD analysis, however after LC-MS/MS analysis, 6 samples showed fumonisin contamination at trace levels (LOQ: 0.05 ng/g).