From another Tweet (@Kontan_Bigcat), a link to a chart giving the latest (Sep. 1) results of testing for radioactivity in rice (Japanese only).  The limit set by the government is 20 Bq/kg. The chart lists the prefectures starting with the ones with rice at less than 1Bq/kg. Testing is for Cs-134 and Cs-137.  There are also links to pages explaining the rationale for setting the limit at 20Bq/kg, and other related resources.

「お米の検査の定量下限/検出限界一覧」Ver.3.0(9/1公表分まで)

【 1 Bq/kg以下】(合計 2 Bq/kg以下)

岐阜県 (検出下限: Cs-134、Cs-137 各 1 Bq/kg)

兵庫県 (検出下限: Cs-134、Cs-137 各 1 Bq/kg)

山口県 (検出限界: Cs-134、Cs-137 各 0.5 Bq/kg)

via TwitLonger — When you talk too much for Twitter.