Ochratoxigenic fungi and ochratoxin A in defective coffee beans

Defective coffee beans may contain toxins such as ochratoxin A (OTA) and other compounds which affect health. In the present work two coffee producing regions were studied: Cerrado in Minas Gerais and Sorocabana in São Paulo State, with the objective of verifying the presence of ochratoxigenic fungi and OTA in the main defective coffee beans. Coffee samples were surface disinfected and plated directly onto Dichloran Glycerol Agar. Fungal species were isolated and identified. The coffee samples were analyzed for OTA and quantified by High Performance Liquid Chromatography (HPLC) equipment. Aspergillus westerdijkiae and Aspergillus section Nigri were found in both regions, while Aspergillus carbonarius only in Cerrado-MG, especially in defective coffee beans. The sour and black defective beans had the highest OTA concentration being 11.3μg/kg and 25.7μg/kg, respectively. In the defective green (immature) beans, although having the highest proportion (38%), the presence of ochratoxigenic fungi and OTA was low.