Japan has found three incidents of processed rice product imports from China so far this year that contained a variety of genetically modified rice not authorised here, a health ministry official said on Friday. The strain of rice concerned, Bt-63, is a variety that has been modified to resist particular insect pests, but it has not been approved in many parts of the world, and China itself prohibits the export of GM rice. In July 2007, Japan stepped up its testing of rice products imported from China to cover all such imports and check for the unauthorised Bt-63.