Effect of temperature on the growth and ochratoxin a production of the aspergillus section nigri members isolated from dried figs

This study investigated the effects of temperature and incubation time on the growth and ochratoxin A production of three isolates of Aspergillus carbonarius and one Aspergillus niger agg. isolate obtained from dried figs. Optimum growth for all isolates were at 30C while minimum lag phase durations for A.carbonarius isolates were at 25C and for A.niger agg. at 30C. For ochratoxin A (OTA) production, lower optimum temperature values were determined for Aspergillus section Nigri members in comparison to growth temperature. Optimum OTA production was observed at 15-20C and 25C by A.carbonarius and A.niger agg., respectively. Significant amounts of OTA could be accumulated after 3 or 5days of incubation depending on the isolates. Temperature significantly influenced the growth rate and the extension of lag phase and OTA production of all tested isolates (P<0.05), whereas incubation time was only significant for OTA production by A.niger agg.