Wine contamination by ochratoxin A in relation to vine environment

With humid air conditions during the susceptible berry period of 20 days before harvest, combined with a large number of damaged berries and a temperature conducive to both fungus growth and OTA production, critical levels of OTA concentration in wine were observed. Within the range of average daily air temperatures investigated, from 17.2 to 22.8 °C, during the susceptible berry period, 21 °C appeared to be the lower limit below which fungus growth and OTA production were not sufficient to result in critical levels of OTA concentration in wine. In our experiment, an average daily air temperature under 21 °C corresponded to an average minimum daily air temperature under 15 °C, below which fungus growth stopped under in vitro conditions. The importance of the berry sugar content before harvest was also demonstrated and our results suggest that the risk of wine contamination by OTA might be predicted from the number of damaged berries and the berry sugar content, along with climate monitoring.