Gamma radiation inhibits the production of Ochratoxin A by Aspergillus carbonarius. Development of a method for OTA determination in raisins

Ochratoxin A (OTA) is a mycotoxin of great interest to humans for its nephrotoxic effects. The development and validation of an OTA method determination in raisins is described by using High Pressure Liquid Chromatography (HPLC) with Fluorescence Detector (FD). The recovery of the method was 104% while the detection limit (DL) and quantification limit were 0.26 and 0.51 ng g−1, respectively.The effect of gamma irradiation at dose of 10 kGy on the production of OTA by Aspergillus carbonarius in raisins (Vitis vinifera L.) and on OTA in contaminated samples, was investigated. The OTA which was produced by A. carbonarius on the 12th day of incubation, after irradiation, showed that at dose level of 10 kGy, OTA production was not detectable (below the detection limit of the method) compared with the non-irradiated the same day. A dose of 10-kGy gamma radiation applied on 100 ng of OTA, in raisins reduced OTA contamination ~88%. According to the risk assessment analysis the Provisional Maximum Tolerable Daily Intake (PMTDI) of 5.8 ng OTA kg−1 bw, indicates that adult consumers are less exposed, 31.4–78.4 fold lower to OTA by the irradiated raisins.