The first to find radioactive rice was Ibaraki Prefecture, but the governor vows to fight the "baseless rumor" to promote rice from his prefecture.
From Sankei Shinbun (8/19/2011):
茨城県鉾田市で栽培された玄米から放射性セシウムが検出されたことを受け、同県の橋本昌知事は１９日、記者団の取材に応じ「安全性に問題はない。８月下旬の本検査の結果を踏まえた上で、茨城のコメは心配ないと、消費者に説明していきたい」と話し、風評被害の防止に全力を尽くす意向を示した。
As the brown rice grown in Hokota City in Ibaraki Prefecture was found with radioactive cesium, Governor of Ibaraki Masaru Hashimoto answered the reporters on August 19 and said "There is no problem with safety. After the formal testing is complete by the end of August, we will persuade the consumers that there's nothing to worry about consuming Ibaraki rice", and that he will do his best to counter the "baseless rumor".
橋本知事は「１年間食べたとしても心配するレベルではない」と強調。一方で「ほかの野菜からも検出されているのでコメから出てもおかしくないと思っていた」とも述べた。
Governor Hashimoto emphasized safety by saying "It is not the level to worry, even if you eat [the rice] for one whole year". At the same time, he said "Since radioactive cesium has been detected in vegetables, I wouldn't have been surprised to see it detected in rice".
今回、セシウムが検出されたのは予備検査として採取された玄米。１キログラム当たりセシウム１３４が２３ベクレル、セシウム１３７が２９ベクレルの計５２ベクレルで、国の暫定基準値（同５００ベクレル）を大幅に下回っていた。
Radioactive cesium was detected in the brown rice in the preliminary testing. Total 52 becquerels/kg of radioactive cesium was found, with 23 becquerels/kg of cesium-134 and 29 becquerels/kg of cesium-137. The amount was far below the national provisional safety limit (500 becquerels/kg total radioactive cesium).
Governor Hashimoto is a former career bureaucrat and a graduate of Tokyo University.
Next to detect cesium in rice was Chiba.
From Mainichi Shinbun (8/26/2011):
千葉県は２５日、福島第１原発事故による放射性物質の影響を調べる収穫前のコメの予備調査で、同県白井市で栽培されたもち米「こがねもち」から、１キロ当たり４７ベクレルの放射性セシウムを検出したと発表した。国の暫定規制値（同５００ベクレル）を大幅に下回ったが、コメの検査で放射性セシウムが検出されたのは、茨城県鉾田市に次ぎ全国で２例目。
Chiba Prefecture announced on August 25 that 47 becquerels/kg of radioactive cesium was found in the mochi-rice (glutinous rice) grown in Shirai City in Chiba Prefecture in the preliminary test before the harvest to survey the effect of radioactive materials from the Fukushima I Nuclear Power Plant accident. The amount of radioactive cesium was far below the national provisional safety limit (500 becquerels/kg). It is the second case of radioactive cesium detection in the country, the first one being in Hokota City in Ibaraki Prefecture.
千葉県安全農業推進課によると、白井市内２地点で２２日に採取した玄米を検査。うち１地点で放射性セシウム１３４が２２ベクレル、同１３７が２５ベクレル検出され、計４７ベクレルだった。同県は８月末をめどに収穫後の玄米を本調査する方針で、規制値以下なら出荷が可能となる。
According to the division for safe agriculture promotion in Chiba prefectural government, the brown rice taken at two locations within Shirai City on August 22 was tested. From one location, 47 becquerels/kg of radioactive cesium was detected, with cesium 134 22 becquerels/kg and cesium-137 25 becquerels/kg. The prefectural government plans to conduct the full survey on the brown rice after the harvest by the end of August, and if the rice tests under the provisional safety limit it will be allowed to be shipped.
But in Fukushima, hardly any radioactive cesium was detected in the early harvest rice.
From Yomiuri Shinbun (8/26/2011):
福島県は２６日、二本松市の旧大平村、本宮市の旧和木沢村、旧荒井村、郡山市の旧喜久田村の田んぼで収穫された早場米の放射性物質の検査結果を発表した。
Fukushima Prefecture announced on August 26 the test results of the early-harvest rice harvested in a location in Nihonmatsu City, two locations in Motomiya City, and one location in Koriyama City.
旧大平村のコメからは放射性セシウムが１キロ・グラム当たり２２ベクレル（暫定規制値５００ベクレル）、ほかは検出されなかった。県は同日、旧荒井村以外の３地区については、旧市町村単位のすべての田んぼの検査で問題がなかったとして、出荷を認めた。東京電力福島第一原発の事故後、同県のコメの出荷は初めてとなる。
From the location in Nihonmatsu City, 22 becquerels/kg of radioactive cesium was found. No radioactive cesium was detected in all the other locations. Based on the results, the prefectural government has allowed the rice harvested in these locations, except for one in Motomiya City, to be shipped. It will be the first shipment of rice from Fukushima after the Fukushima I Nuclear Power Plant accident.
県によると、検査したのは２５、２６日に収穫された早稲種の「五百川」と「瑞穂黄金」の玄米。旧大平村のコメも白米にして検査したところ、放射性物質は検出されなかった。旧荒井村については、すべての田んぼの検査が終わり、規制値を下回れば出荷が認められる。
According to Fukushima Prefecture, two types of early-harvest rice harvested on August 25 and 26 were tested. When the rice in the Nihonmatsu City location was milled, no radioactive materials were detected. As to the location in Motomiya City (Arai-mura), the testing was done on all rice fields. If the results show the level of radioactive cesium is less than the provisional safety limit, the rice will be allowed to be shipped.
These cities are located in "Naka-dori" (middle third) of Fukushima Prefecture where highly radioactive rice hay has been found. 500,000 becquerels/kg of cesium was found in rice hay in Koriyama City, and in Motomiya City, 57 kilometers west of Fukushima I Nuke Plant, the number was even higher at 690,000 becquerels/kg.
For your reference,
Fukushima's radioactive cesium detection limit, according to the prefecture: 10 becquerels/kg
Radioactive cesium (cesium-137) in rice in Fukushima before the accident: ND to 0.14 becquerels/kg, after milling
Radioactive cesium (cesium-137) in rice in Chiba before the accident: ND, after milling
Radioactive cesium (cesium-137) in rice in Ibaraki before the accident: ND to 0.045 becquerel/kg, after milling
(source data for radioactive cesium in rice in Fukushima, Chiba, Ibaraki from Japan Chemical Analysis Center, from 2000 to 2009)