The whole liver thing is a myth shrouded in a partial truth. When looking at toxin accumulation in animals it is almost always most largely concentrated in fat. This is not a problem if you're eating some natural cows, but if you give cows the foie gras treatment (massive feeding of grains) you end up getting fatty liver. This brings with it a potential accumulation of toxins and also impedes the liver's ability to efficiently complete the toxin removal process.
"You can demonstrate the purpose and limits of human digestion with a simple experiment: eat a steak with some whole corn kernels, and see what comes out the other end. It won’t be the steak."