Morphological Characterization and Determination of Aflatoxigenic and Non-Aflatoxigenic <i>Aspergillus flavus</i> Isolated from Sweet Corn Kernels and Soil in Malaysia

This study aimed to morphologically characterize and determine the aflatoxigenic and non-aflatoxigenic <i>Aspergillus flavus</i> isolates. Forty isolates of <i>A. flavus</i> were obtained from sweet corn kernels and soil samples collected from Kampong Raja, Rose Valley, Kea, and Klebang farms in Malaysia. They were cultured on potato dextrose agar (PDA), dichloran rose-bengal chloramphenicol (DRBC), <i>Aspergillus</i><i>flavus</i> and <i>Aspergillus parasiticus</i> agar (AFPA), and coconut cream agar (CCA). Macromorphological characteristics were determined by observing the colony color and texture, while the micromorphological characteristics were determined by examining the spore color, size, structure, conidiophore structure, and vesicle shape. The production of aflatoxin was determined by direct visualization of the UV fluorescence of <i>A. flavus</i> colonies on CCA. Aflatoxin was qualitatively detected in 18 (45%) isolates of <i>A. flavus</i> using UV fluorescence screening while the remaining 22 (55%) isolates did not exhibit any aflatoxin production. The highest incidence of <i>A. flavus</i> (30%) and aflatoxin production (15%) was recorded in samples from Kampong Raja. On the other hand, isolates from Rose Valley (17%) and Kea (12%) were non-aflatoxigenic. Klebang recorded a 25% incidence of <i>A. flavus</i> in which 15% were aflatoxigenic while 10% were non-aflatoxigenic. The occurrence of aflatoxin-producing <i>A. flavus</i> emphasizes the need for the measure to eradicate their presence in food crops. A biological control treatment utilizing the non-aflatoxigenic strains to compete with the aflatoxigenic ones is underway. Validation of aflatoxin production through high performance liquid chromatography is also ongoing.