Aflatoxin (AF) B1, B2, G1 and G2 were determined in 120 samples of selected Thai commodities including unpolished rice, unpolished glutinous rice, chilli powder, whole dried chilli pods and raw peanut. The mean concentrations of the total AFs for analysed samples were 0.16, 25.43, 14.18, 6.62 and 1.43 µg kg(-1) with positive incidences of 4%, 20%, 97%, 37% and 30%, respectively. Quantitative analysis was performed using HPLC equipped with post-column derivatisation and fluorescence detection. Sample clean-up was carried out using immunoaffinity columns for selective enrichment of AFs. The method was validated by using certified reference material, which showed recoveries over 85%. The limit of detections (LODs) and limit of quantifications (LOQs) were in a range between 0.01-0.11 µg kg(-1) and 0.03-0.38 µg kg(-1), respectively. The results clearly demonstrated that AFs were detectable in different matrices. Chilli powder was found to have the highest level of AFs contamination followed by chilli pods, peanut and rice, respectively. However, among the selected commodities, unpolished rice contained only trace levels of AFB1 and AFB2. With regard to the fact that AFs are a natural contaminant in commodities, this report calls to attention the regular monitoring and effective control of food commodities to prevent health hazards.
Keywords: HPLC; aflatoxins; chilli; peanut; rice.