Effect of processing on ochratoxin A (OTA) content of coffee.

Coffee production can be roughly separated into three main steps 1) cherry processing to green coffee beans, 2) storage and transportation of green coffee to the place of consumption, and 3) green coffee processing to roasted and ground coffee and soluble coffee. The mold species which are known to produce ochratoxin A (OTA) in coffee have been identified as Aspergillus ochraceus, A. carbonarius and occasionally, A. niger. The length of time spent at a water activity > 0.80 at any moment until roasting defines the risk of mold growth and OTA production. However, the specific moment and locus of contamination have not yet been clearly identified. Since coffee husks are a significant source of OTA contamination, cleaning and grading of green coffee are effective methods for reducing OTA levels in coffee. During the process of converting green coffee to roasted and soluble coffees, up to 90% reduction in OTA levels can occur.