Ecophysiological Conditions Affecting Growth and Ochratoxin A Production by Aspergillus terreus HA2 and Aspergillus fumigatus HA1 Isolated from Egyptian Rice Grains
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. EKB Journal Management System, 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". EKB Journal Management System, 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', EKB Journal Management System, 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. EKB Journal Management System, 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

Egyptian Journal of Botany
Article 7, Volume 56, Issue 2, February 2016, Page 451-469  XML PDF (550.12 K)
DOI: 10.21608/ejbo.2016.1145
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Authors
Hala. A. Ammar* 1; Eman A. Helmy2
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.

Keywords
Ochratoxin A; A. fumigatus; A. terreus; Ecophysiological Conditions; Grains; water activity; Temperature; Incubation time
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