Every time you save a game a backup is made. If the save has become corrupt there are safeguards in to stop this file being backed up.
So if you get corruption you should have a BACKUP icon on the LOAD OR START NEW GAME screen. Click the small red icon to the left of the backup text to revert to this backup.
It is a good idea to save or quit to menu once in a while to ensure a backup has been created. It only takes a few seconds.
