Non-specificity of nutritional substrate for ochratoxin A production by isolates of Aspergillus ochraceus

Abiotic factors assayed (water activity, temperature and substrate) affected significantly OTA productions by A. ochraceus. Maximum OTA amounts were detected at 25 °C and 0.98 aw on all substrates tested. The highest OTA accumulations found on the different substrates were: green coffee beans (> 2 mg g−1), barley grains (∼1 mg g−1), YES medium (13.9 μg ml−1) and grape (∼3 ng g−1).