Fumonisins concentrations in maize as affected by physico-chemical, environmental and agronomical conditions

Abstract

The objective of the present work was to investigate factors influencing fumonisins concentrations in maize collected from 58 fields located in seven producing areas of the River Ebro Valley (north-eastern Spain). Factors studied were: moisture content and water activity of the grains, climatic onditions during growth, the use of transgenic (insect-resistant) maize seeds, and commercial drying. Fumonisins were detected in maize at harvest in 48.3% samples at a mean concentration of 632 µg/kg. Warm temperature during flowering coupled with wet weather in the last months preceding harvest were key factors to explain differences in fumonisins concentrations between the growing areas. Also, grain moisture content at harvest above a critical value of 20% (0.93 aW) was a significant condition for fumonisins oduction in mature grains. Results indicated that concentrations of fumonisins may not be reduced in transgenic maize hybrids under low pressure infestation by corn borers. Damp maize after harvest was delivered to seven grain dryers located in the same production areas, and it was subjected to commercial drying until 14% moisture content. The incidence of fumonisins in dried maize was 85.7%, with a mean concentration of 352 µg/kg, indicating that this mycotoxin remained mostly stable from harvesting to drying.