Ochratoxin A contamination of coffee batches from Kenya in relation to cultivation methods and post-harvest processing treatments.

This study set out to assess the relative importance of sound and unsound beans in a batch of coffee with regard to ochratoxin A (OTA) contamination. Initially, unsound beans were found to account for 95% of contamination in a batch of coffee, whatever the methods used for post-harvest processing. It was also found that beans displaying traces of attacks by Colletotrichum kahawae were the greatest contributors to OTA contamination. In a second stage, the study compared the contamination of sound beans with that of beans attacked by Colletotrichum kahawae. On average, beans attacked by Colletotrichum kahawae had a statistically higher OTA content than sound beans (18.0 microg kg(-1) as opposed to 1.2 microg kg(-1)). In addition, the average OTA content in unsound beans varied depending on growing conditions.