Effects of Calcium Oxide and Radiation on Aspergillus flavus Population and Aflatoxins Concentrations in Corn Grains

Aspergillus flavus is one of the hazardous fungi which appear in poor storage conditions. This mold produces dangerous toxins of aflatoxins in corn grains. Hence the investigation of reduction possibility of its growth and toxins is important. In this research the effects of calcium oxide (0, %0.5 and %1) and gamma ray (0, 5, 10, 15 and 20 KGy) on growth of Aspergillus flavus and levels of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1 and aflatoxin G2 (AFG2) were investigated. Analysis of variance showed significant effects of irradiation (P<0.0001), calcium oxide (P<0.001) and their interactions (P<0.0001). Aspergillus flavus and AFB1 and AFB2 toxins decreased with increasing irradiation. Further reduction of AFB1 and AFB2 toxins was observed during accompaniment of 0.5% calcium oxide with irradiation. However, simultaneous application of 1% calcium oxide with radiation prevented and reduced more Aspergillus flavus. AFG1 and AFG2 toxins were not detected in any of the samples. Consequently, with considering 10 KGy standard food irradiation limits, it is recommended that 0.5% calcium oxide concentration before storage and irradiation intensity of 10 KGy after storage were applied for corn grains to control mold growth and production of aflatoxin toxins.