Abstract
Ochratoxin A (OTA) is one of the important mycotoxins found in foods and is expected for determination in many exported foods. The AOAC method was reviewed and modified to determine OTA in roasted coffee and corn surveyed in Bangkok and nearby provinces during the year 2004-2005. The extraction method was cooperated with Immunoaffinity Column (IAC), analyzed by high performance thin layer chromatography(HPTLC) then followed by densitometer for quantitative analysis. This method was employed to analyze OTA in corn and resulted good recovery (58.4-86.0 %) and LOD and LOQ showed value of 0.28 and 0.5 μg/kg, respectively. Of 24 corn samples were found OTA positive 58% (14/24), but none of these should the level higher than 5 μg/kg (as the EU standard allowed). In case of roasted coffee, the result revealed only 3 samples positive among 44 surveyed samples (<1-4.6 μg/kg). Due to the interferences during extraction which may affect OTA in roasted coffee analysis, the recovery at concentration of 5 μg/kg was lower compared to corn analysis. Recovery was 76.8% (ranged 1-20 μg/kg), the LOQ and the LOD were 1 and 0.33 μg/kg, respectively. This study concluded that the situation of OTA contamination in both corn and roasted coffee marketed in Bangkok and nearby provinces is low and these foods are safe and wholesome consume as food or feed.
