Mycotoxin production by aflatoxin B1 (AFB1) -producing Aspergillus flavus
Zt41 and sterigmatocystin (ST) -hyperproducer Aspergillus creber
2663 mold strains on corn and rice starch, both of high purity and nearly identical
amylose-amylopectin composition, as the only source of carbon, was studied. Scanning
electron microscopy revealed average starch particle sizes of 4.54 ± 0.635 µm and
10.9 ± 2.78 µm, corresponding to surface area to volume ratios of 127 1/µm for rice
starch and 0.49 1/µm for corn starch. Thus, a 2.5-fold difference in particle size
correlated to a larger, 259-fold difference in surface area. To allow starch, a water-absorbing
powder, to be used as a sole food source for Aspergillus
strains, a special glass bead system was applied. AFB1 production of A.
flavus Zt41 was determined to be 437.6 ± 128.4 ng/g and 90.0 ± 44.8
ng/g on rice and corn starch, respectively, while corresponding ST production levels
by A. creber 2663 were 72.8 ± 10.0 µg/g and 26.8 ± 11.6
µg/g, indicating 3–fivefold higher mycotoxin levels on rice starch than on corn starch
as sole carbon and energy sources.
