After losing three saves already since release, and countless hours working on awesome builds, my buddy and I came up with an idea on how to avoid this from happening.
Your best bet at this point is to go into your "Saved Game Utility" in the PSN menus, plug a USB drive into your PS3, and copy your save file to this USB every so often, depending on how much you play. This obviously won't prevent corrupted saves from happening in general, however - say you're 12 hours of work into a world - copy your save to your USB. Let's say you play for 5 more hours, then the next time you get on, you get the "corrupted save" message. Delete your save, and then copy your last save from your USB to your PS3.
Now obviously, you will lose whatever work you've completed between copying the file and the recent save, HOWEVER, you'll still be able to access your world from that previous save point. From there, just be sure to continue to copy your save over to your USB every so often.
We've started doing this and haven't run into the corrupted save problem again, yet, however, I'm sure it's coming eventually, and I'd rather lose 5 or even 10 hours of work as opposed to losing the entire world completely and not even being able to access it at all.
NOTE: Also, if you're a PSN Plus member, you can avoid all of this, since your saved game utility should be uploaded to their cloud system every so often.