[geoschmo]

My actual knowledge isn't any more then yours, but my best guess would cause me to be a little more optimistic. Our bodies don't really need specific types of plant and animal matter afterall. Our digestive system breaks those down into the basic nutrient blocks that our body does need. And those basic nutrients should be pretty much the same, despite being combined in radically different ways. Of course our survivors would probably need a chemist or botanist and some laboratory equipment to be able to determine what is safe to eat and what's not. Since we wouldn't have millions of years of common memory to rely on.