Cesium is not Iodine, and it's still not safe to eat

This is a decent informative article from NaturalNews.com about radioactive cesium vs. iodine. While the tone is a little alarmist, the information is accurate.

When you hear about "radiation levels" at Fukushima, you're mostly hearing only about radioactive iodine, which decays much, much faster (i.e., days rather than years) than all the other radioactive isotopes one could measure there today. Cesium takes 30 years to decay by half. A tiny bit of radioactive cesium eaten in the body of a contaminated fish caught from the Pacific Ocean - or seaweed grown there - is infinitely more dangerous to you than a particle floating around the atmosphere.  

An illustrative example, from the link:

"A speck of radioactive dust that's one meter away from you, for example, is twice as dangerous as that same speck four meters away. But if you eat that radioactive speck (because it's part of a fishyou're consuming, for example), then suddenly it'sinside your body. So now it might only be a millimeter away from your internal tissues, meaning you've decreased the distance between you and the radiation source byone thousand times. Because if the law of the inverse square of the distance, you have now magnified the radiation intensity byone million times(because one million is the square of one thousand)."

This is the real danger of cesium and other radioactive isotopes - once you eat them, they emit radiation from inside your body, in your muscle tissue or bones or heart or wherever. 

"[Y]ou quickly become a walking radioactive dirty bombfrom the inside."