Impacts of climatic conditions on aflatoxin B1 and fumonisins contamination of maize kernels and their co-occurrence

Agroecological and climatic conditions in Serbia greatly affected the development of toxigenic fungi and occurrence of mycotoxins in the maize. The presence of fungal toxigenic Aspergillus and Fusarium species and levels of aflatoxin B1 (AFB1) and sum of fumonisins B1, B2 and B3 (FBs) were established in 127 maize kernel samples harvested during 2012 (37 samples) and 2013 (90 samples). The periods of silking and grain filling of the maize in 2012 in comparison to 2013 were characterised with extremely dry spells, with high temperatures and low precipitation sums. The mean incidences of A. flavus and F. verticillioides were 50.4 and 11.7% in 2012 and 18.9 and 33.4% in 2013, respectively. According to the regulations of the World Health Organisation, unacceptable levels of AFB1 (>20 μg kg) and FBs (>2000 μg kg) were established in the 30.6 and 24.1% samples of 2012 and 16.7 and 40% maize kernel samples of 2013, respectively. It can be concluded that high temperatures and low precipitation sums in 2012 favoured the development of A. flavus affecting the high level of AFB1 , in comparison with F. verticillioides and the production of FBs. There was no positive correlation between the incidences of A. flavus and F. verticillioides, while a statistically significant positive correlation has been found between AFB1 and FBs levels, in both investigated years (2012-2013). This indicates that the mycotoxin production depended more on weather conditions than on the distribution of corresponding toxigenic fungal species.