Fate of Organophosphorus Flame Retardants in Polished Rice during the Cooking Process

Abstract

The fate of organophosphorus flame retardants (PFRs) in polished rice during the cooking process was examined. After adding PFRs to polished rice (500 ng/g), the rice was washed with water and cooked in a rice cooker. Among the seven kinds of PFRs, approximately 68–86% of the PFRs residues were removed after washing with water three times. In the first washing with water, approximately 50–70% of the PFRs residues were removed from rice. By the subsequent heating in an electric rice cooker or in a microwave rice cooker, the removal rates of PFRs in the cooked rice were 74–94 and 78–96%, respectively. The removal rates in musenmai (500 ng/g) which need not to wash before cooking were lower than those in the washed rice. In the cooked musenmai, 10–50% of the PFRs residues were removed after heating in the electric rice cooker, and 10–70% were removed in the microwave rice cooker. The washing process is effective to reduce the intake of PFRs from rice.