Q & A on Food and Radiation from Consumer Affairs Agency
Please find the answers on your questions about food and its safety in Japan here.
Consumer Affairs Agency: Food and Radiation Q&A (PDF)

Radiation Level in the Air (Tokyo Metropolitan Institute of Public Health)
Environmental radiation levels in Tokyo

Radiation Level in Tap Water (Bureau of Waterworks Tokyo Metropolitan Government)
No radioactive substances have been detected either from raw water or at the water purification plants of Tokyo since April. Latest information related to the effect on purified water by radioactivity