Influence of temperature and water activity on Ochratoxin A production by Aspergillus strain in coffee south of Minas Gerais/Brazil

Abstract

This study investigated the influence of temperature and water activity (aw) on the growth and biosynthesis of Ochratoxin A (OTA) by Aspergillus carbonarius and Aspergillus ochraceus, and the influence of climate change on the production potential of this mycotoxin in coffee was predicted. Central Composite Rotatable Design with aw ranging from 0.91 to 0.99 and temperatures from 17 to 38 °C was used. A. carbonarius CCDCA 10288 and 10293 showed optimal growth in aw intervals from 0.935 to 0.965 and temperatures between 25 and 32 °C while A. ochraceus CCDCA 10211 and 10212 showed aw intervals from 0.940 to 0.990 and temperatures between 21 and 30 °C. The conditions under which strains show the highest OTA risk index are as follows: for A. carbonarius CCDCA 10288 and 10293, aw between 0.95 and 0.99 and temperatures between 22 and 32 °C, for A. ochraceus CCDCA 10211 aw between 0.97 and 0.99 and temperatures between 25 and 30 °C. Using the models obtained, it was possible to verify that the conditions become more favorable for OTA production in the harvest months due to increased temperatures in the southern region of Minas Gerais. A safe product can be ensured by following good practices.