Occurrence and within field variability of Fusarium mycotoxins and their masked forms in maize crops in Belgium

Maize ear rot caused by several Fusarium species is an important fungal disease. Apart from yield losses, ear rot fungi can produce mycotoxins and masked forms in infected grains. Masked mycotoxins have received increased attention in view of their bioavailability and potential toxicity in animals and humans, but their presence and relevance in the field still remain undisclosed. To get a better insight, the present study assessed the presence of various Fusarium parent and masked mycotoxins, i.e. deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, deoxynivalenol-3-glucoside, zearalenone, alpha-zearalenol, beta-zearalenol, zearalenone-14-glucoside, zearalenone-14-sulfate, alpha-zearalenol-14-glucoside, beta-zearalenol-14-glucoside, T-2 and HT-2 toxin, in various commercial maize varieties grown under natural infection conditions in Flanders, Belgium. The results showed that the maize varieties were co-contaminated with both parent and masked mycotoxins. Moreover, a positive correlation between these forms was established. A higher contamination with a particular mycotoxin appeared to be coupled with an elevated load of another (masked) mycotoxin. The results highlight the importance to screen for multiple mycotoxins, both parent and masked, to guarantee food and feed safety. Furthermore, analysis was carried out to elucidate the distribution of the various mycotoxins in the field. The maize variety did not significantly influence mycotoxin accumulation, except for deoxynivalenol. Subdivisions in the field with higher mycotoxin levels for deoxynivalenol and its derivatives, zearalenone and its derivatives, and the sum of T-2 and HT-2 toxin were observed.