Mycotoxins in maize grains grown in organic and conventional agriculture

• We assess the natural levels of fumonisin and DON in maize varieties.
• We find differences among locations for fumonisin but not for DON content.
• There were no differences between organic and conventional environments.
• There is danger of mycotoxin contamination for some varieties in some environments.

Maize is traditionally used for bakery in several countries, and autochthonous varieties are increasingly demanded particularly for organic agriculture, but one of the dangers of cereal consumption is mycotoxin contamination. Mycotoxins are dangerous for health and might be present in any grain depending on genotypes and environments. In the present work we assess the natural levels of fumonisin and deoxynivalenol (DON) contaminations in nine diverse open-pollinated maize varieties grown in four different locations, under organic or conventional conditions, in two regions from the humid Spain during two years. Differences were significant among locations and among varieties for fumonisin contamination but not for DON content. Locations were the main environmental source of variation affecting fumonisins while DON was more affected by years. The Basque locations had more fumonisin than the Galician locations, but there were no differences between organic and conventional environments. Fumonisin contamination was more variable than DON among locations and among varieties. Fumonisin and DON were highly correlated on average but correlations were low for each particular environment. Mean fumonisin and DON were below the threshold allowed by the EU, but the white-kernel medium late variety Rebordanes(P)C2 had more than 4.00 mg/kg of fumonisin in one location, while the early yellow variety Sarreaus had the lowest contamination. We conclude warning producers of the danger of natural contamination with mycotoxins for some varieties in specific environments.