Effect of roasting on ochratoxin A level in green coffee beans inoculated with Aspergillus ochraceus.

The heat stability of ochratoxin A in green coffee beans inoculated with Aspergillus ochraceus was studied. Heat treatment (roasting) at 200 degrees C for 10 or 20 min reduced the levels of ochratoxin A by only 0-12% in the dried whole beans. Almost all of the ochratoxin A was infused into the coffee decoction when the roasted samples were ground and extracted with boiling water. Therefore, the reduction of ochratoxin A concentration of contaminated coffee beans by roasting under these conditions is ineffective.