The incidence of mycobiota and mycotoxin levels were investigated in the
freshly harvested maize kernel samples from October 2014 and in the samples
of stored maize kernels from February 2015. Toxigenic fungal species (moulds)
were isolated, cultivated and identified on agar plates according to standard
mycological methods, while mycotoxins were detected by enzymelinked
immuno-sorbent assay (ELISA). Mycological analyses of kernels showed the
presence of toxigenic species from genera Aspergillus, Fusarium and
Penicillium. Among the Aspergillus species, Aspergillus flavus was identified
with higher incidence in the stored kernels (10.25%), than in freshly
harvested kernels (3.67%) whereas A. parasiticus was the predominant species
in the freshly harvested kernels (4.17%) compared to the stored kernels (0%).
From the genus Fusarium three species were identified: F. graminearum, F.
subglutinans and F. verticillioides, with the incidence of 1.08%, 8% and
25.75%, respectively in freshly harvested kernels and the incidence of 2.50%,
7.10% and 29.75%, respectively in the stored kernels. Species from genus
Penicillium had higher incidence in freshly harvested kernels (14.25%) than
in the stored kernels (9%). In addition, tested samples of harvested and
stored maize kernels were 100% positive with aflatoxin B1 (AFB1),
deoxynivalenol (DON) and total fumonisins B1, B2 and B3 (FBs). The mean
levels of AFB1, DON and FBs were 2.77 ?g kg-1, 117.83 ?g kg-1, and 3700.84 ?g
kg-1, respectively in the freshly harvested kernels and a mean levels of 2.16
?g kg-1, 2034.40 ?g kg-1, and 5976.50 ?g kg-1, respectively in the stored
maize kernels. In the freshly harvested maize kernel samples, statistically
significant (P ? 0.05) positive correlations of kernel moisture content with
the incidence of Penicillium spp. (r = 0.47), and levels of AFB1 (r = 0.46)
and FBs (r = 0.47), and between the incidence of Penicillium spp. and level
of AFB1 (r = 0.53) were established. In the stored maize kernel samples,
statistically significant (P ? 0.05) positive correlations were found between
the incidence of F. subglutinans and level of FBs (r = 0.50) and between
levels AFB1 and FBs (r = 0.52). A highly significant (P ? 0.01) positive
correlation was established between the incidence of F. verticillioides and
level of FBs (r = 0.64) in freshly harvested maize kernel samples. These
results indicate that the incidence of toxigenic fungi and levels of
mycotoxins, in particular DON and FBs, were higher in the stored maize kernel
samples than in freshly harvested maize kernels. Therefore, to prevent the
development of toxigenic fungi and mycotoxins accumulation in post-harvest
period it is necessary to thoroughly dry maize and keep it in hygienic food
storages. [Projekat Ministarstva nauke Republike Srbije, br. TR-31023, br.
TR-31033, br. TR-31053 i br. TR-31081]
