Aflatoxin B1, zearalenone, and deoxynivalenol production on irradiated corn kernels: Influence of inoculum size

MAGNOLI CARINA, ETCHEVERRY MIRIAM, CAVAGLIERI LILIA, SAENZ MARCELA, ALVAREZ GABRIELA Y LECUMBERRY SANDRA

Mycotoxin Research

HWS

Lugar: Alemania; Año: 1998 vol. 14 p. 28 - 34

0178-7888

The influence of inoculum size in the production of aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON) was determined when Aspergillus parasiticus NRRL 3000 and Fusarium graminearum ITEM 124 were culture alone and in pairs on irradiated corn kernels at 28ºC and 0.97 water activity (aw). The highest levels of AFB1 produced by A. parasiticus were produced at the lowest levels of inoculum (103 spores/ml). No signifficnat differences were observed in ZEN and DON production at any inoculum level during the experimental period. When A. parasiticus was co-inoculed with F. graminearum both to the same inocula (106 spores/ml) AFB1 inhibition percentage were 60, 72 and 56% at 10, 20 and 35 days of incubation respectively, while at 106 spores/ml the percentages of inhibition were 34, 84, and 93% at 10, 20 and 35 days. In the mixture cultures A. parasiticus 103 x F. graminearum 106 spores/ml the percentage of inhibition of AFB1 oscillated in 99% during all the incubation. In the interaction A. parasiticus 106 spores/ml x F. graminearum 103 spores/ml the accumulation of AFB1 decreased in 80 , 94, and 86 % at 10, 20 and 35 days of incubation respectively. In single culture F. graminearum was inoculated with 103 or 106 spores/ml and the highest levels of ZEN and DON were detected at 35 days of incubation. The levels oscillated in 538-622 µg/kg for ZEN and 870-834 µg/kg for DON respectively. In paired cultures there were no significant differences in the levels regardless of the spore concentrations during the incubation time.