Ammar, H., Helmy, E. (2016). Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains. Egyptian Journal of Botany, 56(2), 451-469. doi: 10.21608/ejbo.2016.1145
Hala. A. Ammar; Eman A. Helmy. "Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains". Egyptian Journal of Botany, 56, 2, 2016, 451-469. doi: 10.21608/ejbo.2016.1145
Ammar, H., Helmy, E. (2016). 'Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains', Egyptian Journal of Botany, 56(2), pp. 451-469. doi: 10.21608/ejbo.2016.1145
Ammar, H., Helmy, E. Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains. Egyptian Journal of Botany, 2016; 56(2): 451-469. doi: 10.21608/ejbo.2016.1145
Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains
1Department of Botany, faculty of Science, Zagazig University
2The Regional Center for Mycology and Biotechnology,)BMCR( Al-Azhar University,
Abstract
OCHRATOXIN A (OTA) is one of the most significant ……..mycotoxins of worldwide concern for human health. Various fungi which are ubiquitous contaminants of Egyptian cereals, pre- and post- harvest can produce OTA under ecophysiological conditions. Sixty two fungal isolates belonging to four genera have been isolated from Egyptian cereals. Nine isolates have the ability to produce OTA namely; A. ochraceus, A. terreus, A. fumigatus, A. alliaceus, A. carbonarius, A. niger, A. sclerotioniger, A. versicolor and P. verrucosum. The highest OTA producer strains which isolated from Egyptian rice grains are, A. ochraceus, A. terreus and A. fumigatus. A. terreus and A. fumigatus were selected for this study. Both strains show optimum growth rate using Yeast Extract Sucrose (YES) culture medium, incubation temperature at 30 o C with 0.98 water activity (aw) after 7 days. Maximum OTA production has been obtained for both strains at 0.98 aw at 25-30 o C after 14 and 21 days in the culture medium and rice grains respectively. The two strains failed to grow and to produce OTA at 8 o C on YES medium and rice grains at all tested conditions. No OTA was detected at 0.85aw in culture medium, while the two fungal strains couldn‟t grow on rice at the same aw and failed to produce OTA at 0.90 aw at all tested temperature during the 21 days incubation period. Conclusively our results show that the use of different storage practices of water activity (aw) and temperature levels below 0.90 and 20°C, respectively, enhance controlling fungal contamination and minimizing the OTA production in rice grains.
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