Occurrence of Fusarium mycotoxins in maize imported into the UK, 2004–2007

Abstract

This study examined a total of 82 consignments of French and Argentinean raw maize as received at maize mills in the UK between 2004 and 2007. Samples were analysed for deoxynivalenol (DON), nivalenol (NIV), other trichothecenes, zearalenone (ZON), and fumonisins B₁, B₂, and B₃ (FB₁, FB₂, and FB₃) using fully validated analytical methods with limits of quantification of 10 µg kg⁻¹ for DON, NIV, and each fumonisin mycotoxin and 3 µg kg⁻¹ for ZON. All samples except two containing fumonisins met the European Commission statutory maximum permissible levels for DON, ZON, and FB₁ + FB₂ as operating in 2007. The maximum concentrations found for DON, NIV, ZON, and FB₁ + FB₂ were 444, 496, 165 and 5002 µg kg⁻¹, respectively. Fumonisins were detected in almost every sample with 65% of Argentinean maize containing more than 1000 µg kg⁻¹ of FB₁ + FB₂. In contrast, ZON was not detectable in almost 50% of consignments. During this period there was a distinct difference in mycotoxin concentrations between harvests and geographic origin. Flint maize from Argentina usually contained lower concentrations of DON and related trichothecenes and higher levels of fumonisins than maize from France, although concentrations of fumonisins up to 2000 µg kg⁻¹ or greater occurred in samples from both regions. The incidence and concentrations of fumonisins were similar to those in a similar previous survey, while zearalenone concentrations were lower. The distribution of mycotoxins in multi-hold ships was also investigated showing that fumonisins were much more evenly distributed than DON, thus indicating their general level in the ship as a whole. The effect of cleaning regimes was found to be very variable, especially for DON, ranging from no removal of mycotoxins to greater than 50% in some instances, but was not related to concentration. Evidence here suggests that while cleaning is essential for removing foreign bodies before milling, it cannot be used as a reliable tool for reducing mycotoxins.

Keywords:

• deoxynivalenol
• zearalenone
• fumonisins
• nivalenol
• cleaning
• maize

Acknowledgements

These studies were funded by the UK DEFRA, Food Quality and Safety LINK Programme and the UK Food Standards Agency, and would not have been possible without the enthusiastic cooperation and assistance from the staff of the three UK maize mills.