Continual Rising Levels of Cesium in Milk

Please comment on the continually rising Cesium levels in milk.
What we continually hear is don't worry these are still acceptable levels.
Is that kinda like going to the Captain of a ship, and saying that even though the hole in the bottom has been plugged, the water level in the bottom of the ship is still continuing to rise and he says, "It's ok, it won't hurt you, it's a big ship and can take a lot before it sinks"?

Does anyone know the upper level of Cesium biomagnification?
In the case of DDT biomagnification the following chart show that 0.04ppm at the producer level (ie grass in the case of cows) gets magnified to 13.8ppm in Tertiary Consumers. Correct me if I am wrong, but aren't we humans the tertiary consumers in the case of Cesium?
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/D/DDTandTrophicLe...

Since we can already see Cesium biomagnification in cow's milk, in what other foods (untested?) should we expect biomagnification?

Also, since Cesium is being found here, what other persistent radioisotopes should we expect to be in our food which have not been tested for, or at least not publicly disclosed?