Contamination of wheat, barley and maize seeds with toxigenic Fusarium species and their mycotoxins in Tunisia
Abstract Background Fusarium is a worldwide distributed fungal genus. It includes different species pathogenic to cereals among others crops. Some of these species can also produce toxic compounds towards animals and humans. Objective In this work, occurrence of fumonisins B1+B2, zearalenone, type A trichothecenes (T-2 and HT-2 toxins) and type B trichothecenes (deoxynivalenol and nivalenol) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. Methods Mycotoxins analyses were performed by using gas chromatography for type B trichothecenes and high-performance liquid chromatography for other mycotoxins. Obtained results were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction (PCR). Results Fumonisins occurred in 20.83% of wheat, 40% of barley, and 57.14% of maize samples, at levels exceeding European limits and suggesting a risk in Tunisian cereals, especially maize. Zearalenone, deoxynivalenol, nivalenol and T-2+HT-2 toxins were detected at lower values in only wheat and barley samples. PCR protocols showed the predominance of F. verticillioides especially in maize, and occurrence of F. equiseti and F. graminearum in wheat and barley, and F. proliferatum in only 2 maize samples. A very consistent correlation was found between the detection of F. verticillioides and the contamination by fumonisins, as well as between the presence of F. graminearum and the contamination by zearalenone, deoxynivalenol and nivalenol in the analyzed cereals. Conclusions Consequently, the detection of Fusarium species with the current polymerase chain reaction assays strategy in wheat, barley and maize grains may be considered predictive of their potential mycotoxin risk in these matrices.