That's probably worst case but a figure I have heard/read, too. With some animals the radiation level is as high as 5000-10000 Bq/kg.

Here's an interactive map on the topic: http://www.umweltinstitut.org/themen/radioaktivitaet/messung...

To put that figure into perspective, it is said that eating 6 kg of boar meat with 3000 Bq/kg is equivalent to 240 micro Sievert which equates 12 x-rays of the lung.