Effects of Treatment Time and Thickness of Meat on the Removal of Radioactive Cesium from Beef Slices by Boiling and Water Extraction.

Since the Fukushima nuclear accident, radioactive contamination of foods has become a serious concern among the Japanese people. In the present study, the decontamination effects of boiling and water extraction on beef slices containing radioactive cesium were examined, focusing on the effects of beef thickness and treatment time. Boiling effectively decontaminated the beef slices depending on the treatment time and the thickness of the beef. The time needed for 50% decontamination (T-1/2) was estimated at 0.25, 0.89, 2.0, and 20 min for beef slices 1, 2, 4, and 10 mm thick, respectively. Water extraction also decontaminated the beef, but its efficiency was far less than that of boiling; the T-1/2 of water extraction was 6.8, 24, and 187 min for beef slices 2, 4, and 10 mm thick, respectively. The T-1/2 increased nearly in proportion to the square of the thickness of the beef slice; the thinner the slice, the more quickly it was decontaminated. The boiling treatment was approximately 7 to 10 times more effective than water extraction based on the T-1/2 value. Foods currently distributed in the Japanese market do not need to be decontaminated; however, this information will be helpful for people who are anxious about radioactive contamination caused by the nuclear accident.