Effects of γ-radiation on the fungus Alternaria alternata in artificially inoculated cereal samples

• Published in: Applied radiation and isotopes Vol. 67; no. 9; pp. 1622 - 1628
• Main Authors: Braghini, R., Pozzi, C.R., Aquino, S., Rocha, L.O., Corrêa, B.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2009
• Subjects: Alternaria - physiology; Alternaria - radiation effects; Alternaria alternata; Cereals; Colony Count, Microbial; Dose-Response Relationship, Radiation; Edible Grain - microbiology; Edible Grain - radiation effects; Food Irradiation; Food Microbiology; Foods; Fungi; Gamma Rays; Stem Cells; γ-radiation; Fungi; γ-radiation; Cereals; Foods; Alternaria alternata
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2009.03.004

The objective of this study was to evaluate the effects of different γ-radiation doses on the growth of Alternaria alternata in artificially inoculated cereal samples. Seeds and grains were divided into four groups: Control Group (not irradiated), and Groups 1, 2 and 3, inoculated with an A. alternata spore suspension (1×106 spores/mL) and exposed to 2, 5 and 10kGy, respectively. Serial dilutions of the samples were prepared and seeded on DRBC (dichloran rose bengal chloramphenicol agar) and DCMA (dichloran chloramphenicol malt extract agar) media, after which the number of colony-forming units per gram was determined in each group. In addition, fungal morphology after irradiation was analyzed by scanning electron microscopy (SEM). The results showed that ionizing radiation at a dose of 5kGy was effective in reducing the growth of A. alternata. However, a dose of 10kGy was necessary to inhibit fungal growth completely. SEM made it possible to visualize structural alterations induced by the different γ-radiation doses used.