Deoxynivalenol and contaminant mycoflora in freshly harvested Argentinian wheat in 1993

Abstract

A mycological survey was carried out on wheat heads from the main production area of Argentina. The isolation frequency and ++relative density of species from genus Fusarium and dematiaceous fungi were calculated. F graminearum was the predominant Fusarium species; similar to that observed in the USA and Canada. An analysis of deoxynivalenol (DON) natural contamination also was performed on a limited number (44) of samples. DON contamination levels in positive samples ranged from 0.2 to 30 ppm. A stepwise regression procedure showed that, among the species analysed, F. graminearum relative density was related to the DON contamination level and that other prevalent fungi did not influence or modify that relationship.

Natural occurrence of nivalenol and mycotoxigenic potential of Fusarium graminearum strains in wheat affected by head blight in Argentina

“…These results agree with other reports carried out in Argentina where F. graminearum proved to be the main toxigenic Fusarium species (10,15,20). All the samples collected in the zones IIN and IIS are 100% infected.…”

“…On the contrary, zone V can be considered less contaminated because 71.42% of samples don't reach 100% of infection. In fact, F. graminearum is the most frequent fungi in the zone IIN and IIS while the percentages are lower in the zones IV and V. The levels of toxin contamination found in samples in this study are similar to those reported earlier in heavily infected wheat in Argentina (10,19). This is the first report of the natural occurrence of NIV in wheat cultivated in Argentina.…”

“…Therefore the presence of NIV in Argentinean wheat may have a significant impact on the food safety aspects because its presence can synergize the toxicity of DON. By this study and other reports (5,10,19) Argentina prove to have a high risk of DON wheat contamination due to the high incidence of FHB, particularly in the area with temperate humid climate. This risk seems also to be present in South of Brazil (9) and Uruguay (18).…”

“…(11). Some earlier works have shown that F. graminearum was the main occurring species and deoxinivalenol (DON) was the main toxin contaminant detected in wheat and wheat-products in Argentina (10,18,19,20). Two main chemotypes were reported in G. zea from rice in Japan: the "NIV chemotype" which produces nivalenol (NIV) and Fusarenone X (Fus-X) and the "DON Chemotype" which produces deoxinivalenol (DON) and its acetylated forms (12).…”

Ocorrência de desoxinivalenol em trigo nacional e importado utilizado no Brasil

“…RIZZO et al 22 avaliando a presença de toxinas em trigo da sub-região tritícola no norte da Argentina detectaram entre as amostras somente o DON em níveis que variaram de 2.000 a 28.000 µg.kg -1 . O trigo argentino da safra de 1993 proveniente de 2 regiões de maior produção foi analisado por GONZALEZ et al 16 Ao contrário dos trabalhos anteriormente citados, no presente levantamento constatou-se que o trigo importado apresentou níveis baixos de contaminação sendo significativamente inferiores aos do trigo nacional (p ≤ 0,05). Nas amostras de trigo importado, o maior nível de contaminação detectado foi de 349 µg.kg -1 , enquanto no trigo nacional observou-se uma contaminação máxima de 4.573 µg.kg -1 .…”