Impacts of climatic conditions on aflatoxin B 1 and fumonisins contamination of maize kernels and their co-occurrence

Abstract

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 B 1 (AFB 1) and sum of fumonisins B 1 , B 2 and B 3 (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 AFB 1 (>20 μg kg-1) and FBs (>2000 μg kg-1) 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 AFB 1 , 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 AFB 1 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.

Agroekološki i klimatski uslovi u Srbiji veoma su pogodni za razvoj toksigenih gljiva i njihovih mikotoksina u kukuruzu. Prisustvo toksigenih vrsta gljiva iz rodova Aspergillus i Fusarium, kao i nivoi aflatoksina B1 (AFB1) i ukupnih fumonizina B1, B2 i B3 (FBs) utvrđeni su u 127 uzoraka zrna kukuruza iz berbe tokom 2012 (37 uzoraka) i 2013. godine (90 uzoraka). U fenofazama svilanja i nalivanja zrna kukuruza u 2012. u odnosu na 2013. godinu zapaženi su ekstremno sušni periodi sa visokim temperaturama i niskim količinama padavina. Prosečne vrednosti za učestalost vrsta A. flavus i F. verticillioides bile su 50,4 i 11,7% u 2012., odnosno 18,9 i 33,4% u 2013. godini. Prema pravilniku Svetske zdravstvene organizacije (WHO) nedozvoljeni nivoi AFB1 (>20 µg/kg) i FBs (>2000 µg/kg) utvrđeni su u 30,6% i 24,1% uzoraka u 2012., odnosno u 16,7% i 40% uzoraka u 2013. godini. Na osnovu dobijenih rezultata zaključeno je da su visoke temperature i niske količine padavina u 2012. godini uslovile značajno veću učestalost A. flavus i visoku produkciju AFB1 u poredjenju sa vrstom F. verticillioides i produkcijom FBs. U obe ispitivane godine (2012-2013), između učestalosti A. flavus i F. verticillioides nije ustanovljena pozitivna korelacija, dok je statistički značajna pozitivna korelacija ustanovljena između nivoa AFB1 i FBs. Ovo ukazuje da produkcija mikotoksina je više zavisna od vremenskih uslova u odnosu na distribuciju toksigenih vrsta gljiva.