Skip to main content
Article thumbnail
Location of Repository

Influence of physiological factors on growth, sporulation and ochratoxin A/B production of the new Aspergillus ochraceus grouping

By Ahmed Abdel-Hadi and Naresh Magan


Recently, new species within the Aspergillus section Circumdati group responsible for ochratoxin production were reported. This study has examined the impact of interactions between water activity (aw, 0.99-0.90), temperature (20-35 °C) on growth, asexual spore production and ochratoxin A and B (OTA and OTB) on strains of each of the three species from this new grouping (A. ochraceus, A. steynii, and A. westerdijkiae) for the first time. The maximum growth occurred at 0.95 aw and 30 °C for both A. ochraceus and A. westerdijkiae, while it was at 0.99 aw and 30 °C for A. steynii. No conidial spore production occurred at 0.99 aw in cultures of A. ochraceus and A. steynii but large numbers of spores (2.3×107/cm2) were produced by A. westerdijkiae. Optimum temperature for spore production was 0.95 aw and 30 °C for A. westerdijkiae and A. ochraceus, and 0.95 aw and 35 °C for A. steynii. Quantification of OTA showed that optimum was produced at 0.99 aw, by A. steynii at 30 °C, for A. westerdijkiae at 25 °C and for A. ochraceus at 20 °C. As water stress was imposed (0.95 aw), the temperature for maximum OTA production changed. For example, for A. steynii and A. westerdijkiae this was at 35 °C, for A. ochraceus, 25 °C. Much less OTB was produced relative to OTA, but the production followed the same pattern at all aw levels and temperatures. This is the first detailed study to examine the similarities and differences in ecology of these related species in this important mycotoxigenic group

Topics: Aspergillus ochraceus group, water activity, temperature, ochratoxin, sporulation
Publisher: Wageningen Academic Publishers
Year: 2009
DOI identifier: 10.3920/WMJ2009.1156
OAI identifier:
Provided by: Cranfield CERES

Suggested articles


  1. (2008). Effect of solute, matric potential and temperature on in vitro development of Aspergillus flavus strains from Italy. doi
  2. (1998). Effect of water activity and temperature on growth and ochratoxin production by three strains of Aspergillus ochraceus on a barley extract medium and on barley grains. doi
  3. (2004). Emericella astellata, a new producer of aflatoxin B1, B2 and sterigmatocystin. doi
  4. (1999). Influence of water activity and nutrient on growth and production of squalestatin S1 by a Phoma sp. doi
  5. (2001). Influence of water activity and temperature on the growth of Wallemia sebi: application of a predictive model. doi
  6. (1988). Influence of water activity of a solid substrate on the growth rate and sporogenesis of filamentous fungi. doi
  7. (1996). International Commission on Microbiological Specification for Foods (ICMSF), doi
  8. (1994). Ochratoxin A production by strains of Aspergillus niger var. niger. Applied and Environmental Microbiology. doi
  9. (1992). Ochratoxin A—a mycotoxin of concern. In:
  10. (2002). Ochratoxin production by the Aspergillus ochraceus group and Aspergillus alliaceus. Applied and Environmental Microbiology. doi
  11. (1999). Osmotic and matric potential effects on growth, sclerotia and partitioning of polyols and sugars in colonies and spores of Aspergillus ochraceus. doi
  12. (2003). Post-harvest fungal ecology: impact of fungal growth and mycotoxin accumulation in stored grain. doi
  13. (2001). Production of ochratoxin A by Aspergillus carbonarius on coffee cherries. doi
  14. (2005). Relationship between aflatoxin synthesis and Aspergillus flavus development.
  15. (2006). Signalling pathways connecting mycotoxin production and sporulation. doi
  16. (2003). The role of water in solid-state fermentation. doi
  17. (1995). The stored-grain ecosystem. In doi
  18. (2004). Water activity, solute and temperature modify growth and spore production of wild type and genetically engineered Aspergillus niger strains. Enzyme and Microbial Technology. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.