Some readers were wondering if radioactive cesium had been detected in the type of Japanese green tea in fine powder - maccha (抹茶). So I googled it, and up came the report by Seikatsu Club (co-op), as follows:
Maccha 早春の香 (Shinsei Watarai-cha): total cesium 11 Bq/kg. Tea was made [into maccha form] in April.
Maccha 早春の香 (Shinsei Watarai-cha): total cesium 66 Bq/kg. Tea was made [into maccha form] in March.
Maccha 早春の香 (Shinsei Watarai-cha): total cesium 37 Bq/kg. Tea was made [into maccha form] in April.
There is no information when the tea was picked.
Shinsei Watarai-cha is an organic tea grown in Watarai-cho in Mie Prefecture.
On checking the environmental database by Japan Chemical Analysis Center, I've found that the highest level of radioactive cesium (Cs-137) in green tea in Mie Prefecture was in 1988 at 2.9 becquerels/kg. In the past 10 years, it was either "not detected" or less than 0.1 becquerels/kg.
Watarai-cho is located just southwest of Ise City in Mie. Ise City is famous for the Ise Grand Shrine.
By the way, Mie Prefecture is accepting the disaster debris from Iwate and Miyagi. The governor of Mie signed the agreements with his counterparts in Iwate and Miyagi, despite oppositions from mayors in Mie, including the mayor of Ise City and the mayor of Watarai-cho.
UPDATE: comments from people I follow on Twitter:
Kontan_Bigcat: 7 to 9 becquerels/kg of cesium was detected last year from tea in Mie.
Kouta Kinoshita: it is possible that the number is high relative to the level of contamination in Mie, because the tea was organically grown.
The tea that was made into maccha tea was from Aichi Prefecture, east of Mie Prefecture, even though the company who made the maccha tea is a tea grower and blender in Mie Prefecture.