Occurrence of aflatoxins in export-quality Pakistani rice

A survey was conducted to assess the extent of aflatoxin B1, B2, G1 and G2 contamination of export-quality rice. Five hundred and nineteen batches of rice (including white, brown and sella rice) from various exporters were analysed for aflatoxins using Mycosep column clean-up and quantification with high-performance liquid chromatography, during the year 2010. Mean concentrations for aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) were 0.56 µg kg–1 and 0.03 µg kg–1 for brown rice, 0.49 µg kg–1 and 0.03 µg kg–1 for white rice and 0.73 µg kg–1 and 0.02 µg kg–1 for sella rice, with an overall positive (≥ the limit of detection of 0.1 µg kg–1 for AFB1 and AFG1; and 0.05 µg kg–1 for AFB2 and AFG2) incidence of 49%. Out of all analysed samples, only 1.9% was found positive for aflatoxin G1. Highly contaminated samples were found in the month of August, with findings for aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) of 16.65 µg kg–1 and 2.64 µg kg–1, respectively. During the whole year, monitoring aflatoxin concentrat...