Alternating temperatures and photoperiod effects on fungal growth and Ochratoxin A production by Aspergillus carbonarius isolated from Tunisian grapes

The effect of three alternating temperatures cycles (20/30, 20/37 and 25/42 °C) and photoperiod on growth and Ochratoxin A (OTA) production of six isolates of Aspergillus carbonarius on synthetic nutrient medium were investigated.The different temperature regimes affected significantly both the mycelial growth and the OTA production. The best growth and OTA production were recorded at 20/30 °C. The isolates from the region of Baddar produced the highest OTA yields. A 24 h light cycle generally enhanced the growth of A. carbonarius. Growth rates cycles of 11 h/13 h light/darkness and 24 h darkness were often similar for individual isolates, such conditions enhanced OTA production in two of the six isolates tested.