Five-year survey of ochratoxin A in processed sultanas from Turkey.

The results of surveillance for ochratoxin A (OTA) in 1885 samples of sultanas taken during five crop years between 1999 and 2003 are reported. The analytical method was based on extraction with methanol + sodium bicarbonate and clean-up by immunoaffinity column chromatography followed by high-performance liquid chromatography with fluorescence detection. The limit of detection for OTA was 0.3 microg kg(-1). The results show that 9.3% of the samples contained no detectable levels of OTA, whereas 0.6% had concentrations exceeding 10 microg kg(-1); the remaining 90.3% had levels within the range 0.3-10 microg kg(-1). The overall mean OTA concentration in the total number of 1885 samples taken was 1.36 +/- 2.91 microg kg(-1); the overall median was calculated as 0.90 microg kg(-1).