The Influence of Temperature on the Growth of Mould Aspergillus ochraceus NRRL 3174 and on Ochratoxin A Biosynthesis in Pure and Mixed Culture
F. Delaš*1, S. Duraković1, Ivančica Delaš2, Božica Radić3, Ksenija Markov1
1Laboratory of Microbiology, Faculty of Food Technology and Biotechnology, University of Zagreb, 10 000 Zagreb, Pierottijeya 6, Croatia
2Department of Chemistry and Biochemistry, School of Medicine, University of Zagreb, Šalata 3, Croatia
3Laboratory of Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Ksaverska cesta 2, Croatia
Article history:
Received June 29, 1995
Accepted December 6, 1995
Summary:
In the present study the growth of ochratoxigenic mould Aspergillus ochraceus NRRL 3174 and ochratoxin A (OTA) synthesis lucre investigated during the cultivation of the mould on corn grains in a pure culture, as well as in a mixed culture with the non-ochratoxigenic mould Trichotheciuin roseuni ZMPBF 1226. The amount of synthesised biomass was determined indirectly by measuring the cliilin, while the quantification of OTA was performed fluorodensitomctrically. During the 35 days cultivation of the tested mould in a stationary culture at temperatures 15 °C, 20 °C, 25 °C and 30 °C, and the water content in the substrate of 38 %, the highest concentration of OTA was reached at 20 °C. At higher temperatures, 25 °C and 30 °C, the biomass synthesis was increased, bul at the same time OTA synthesis decreased. OTA concentration was maximal after 14 days of cultivation. A mixed culture of the tested moulds reduced OTA bio-synthesis, and after 14 days the OTA concentration dropped to 50-60 % of the highest value obtained in the pure culture.
