Ochratoxin A in liquorice as affected by processing methods.

A study of the effect of several processing methods on the concentration of ochratoxin A (OTA) in liquorice and derived products was carried out. The effect of the sorting, washing and peeling of fresh liquorice roots was investigated; as well as the production at a laboratory scale of liquorice extract and block liquorice from dry roots. Finally, the thermal stability of OTA was assessed. The OTA content was analysed by high-performance liquid chromatography-fluorescence and confirmed by methyl ester formation. The OTA level in liquorice extract was stable to heat treatment at 150 degrees C for 60 min. The OTA concentration was unaffected by sorting or washing, but it was much reduced by peeling (a 53.1% reduction). A great reduction in the OTA level was found during the production of liquorice extract (78.6%) and block liquorice (91.8%).