About 1,500 cows that were fed hay containing radioactive cesium in excess of the government limit were found to have been shipped from Fukushima and other prefectures to all of Japan except Okinawa, as of Thursday.

The cows ate hay that was left outside after the hydrogen explosions at the Fukushima No. 1 nuclear plant's reactors in mid-March.

Some consumers have already eaten meat from the cows, raising questions about whether it remains safe to eat beef, or even chicken and pork.