There's a lot of manufacturing (particularly semiconductor related) in that part of the country, so if it was an issue it'd be popping up in all sorts of products all over the world, not just ones from Japanese companies and/or assembled in Tohoku. It shouldn't be an issue becuase it's not as if it is put together from raw materials that were outside and exposed to the radioactive cesium. Even most of the rubble from the earthquake/tsunami which was outside and potentially exposed has had very low radioactivity readings.
That said, I don't have complete faith in the testing regimes and transparency of the Japanese authorities and even though everything that makes it to market is supposedly safe, I tend to avoid foodstuffs grown in so I'm also partially guilty of contributing to the further economic troubles the region is facing.
Cesium scatter map
http://dwqovw6qi0vie.cloudfront.net/article-imgs/en/2011/11/21/AJ201111210014/AJ201111210095.jpg