Reduction of Aflatoxin-B1 and Ochratoxin-A levels in Polished Basmati Rice (Oryza sativa Linn.) by Different Cooking Methods

Rice (Oryza saliva Linn.) is one of the basic diets of Pakistan, The aim of present study was to evaluate the effect of different cooking methods on the levels of aflatoxin-B-1 (AFB(1)) and ochratoxin-A (OTA). For this purpose the rice samples were artificially contaminated with AFB(1) and ochratoxin-A (OTA) individually and simultaneously. The samples were then submitted to three different cooking methods i.e. normal cooking, cooking in an excess of water and in a microwave oven. After treatment, the both toxins were determined by thin layer chromatography (TLC) technique. The highest mycotoxin reductions were observed when rice samples cooked in excess water (87.5 % for AFB(1) and 86.6 % for OTA), followed by normal cooking (84.0 % for AFB(1) and 83.0 % for OTA) and microwave oven cooking (72.5 % for AFB(1) and 82.4 % for OTA). The samples artificially contaminated with both AFB(1) and OTA, the highest reductions were also observed for rice cooked in excess water (87.5 & 83.0 %) than cooked by normal cooking (82.5 & 76.6 %), and by microwave oven cooking (77.6 & 75.9 %). The rates of toxin reduction were relatively lower in samples artificially simultaneously contaminated with AFB(1) and OTA, than the rice samples contaminated with AFB(1) and OTA individually.