Fusarium mycotoxins in milling streams from the commercial milling of maize imported to the UK, and relevance to current legislation

Abstract

A study in three large commercial UK maize mills showed that Fusarium mycotoxins, such as deoxynivalenol, zearalenone and fumonisins present at mill intake, are distributed in milling streams approximately according to their occurrence in the maize seed structure. Fractions derived from the endosperm tended to contain the lowest levels of mycotoxins. Concentrations of mycotoxins within the endosperm are also related to the particle size. However, the products derived from the embryo or outer seed layers contained the highest mycotoxin levels being concentrated up to five times or more, although these components are normally used for animal feed or industrial use. The general pattern of mycotoxin distribution found when milling French and Argentinean maize was similar, although very variable, and it is concluded that this variability stems from different milling strategies used at each mill and from the nature and condition of each consignment of maize. Mycotoxins in maize grits (particle sizes >500 µm) were usually reduced by the greatest amount when compared with the whole maize, while flour (≤500 µm) could be both reduced or increased depending on the mill and consignment. Thus, in most situations mycotoxin concentrations in whole maize that meet European Commission legislation on intake should give rise to levels in milled ingredients that should also do so. However, this was not always true in some ingredients, especially for fumonisins in those fractions with particle size ≤500 µm.

Keywords:

• maize
• deoxynivalenol
• zearalenone
• fumonisins
• nivalenol
• milling
• flour
• grits
• bran

Acknowledgements

These studies were supported by the UK Department for Environment, Food and Rural Affairs (DEFRA), LINK Programme UK, Food Standards Agency, and the UK maize milling industry.