Silver-Age Superman has got to be THE most paranoid superhero ever written when it comes to his secret identity. The most. EVER. I mean, come on, man - just how many people have touched that saltshaker? It's in a diner! Every third or fourth person who comes in there must use the thing - its surface must be smeared with dozens of the things. A skilled forensic team couldn't get an identifiable print off of something like that even if they looked at it for weeks. And even if, by some miracle, the saltshaker WAS completely untouched when he touched it earlier, it ain't gonna stay that way for very long. If you don't trust someone else to come along and touch it, just spill some soup on it or something - you don't have to EAT it. I mean, ewww. I think that, had the Weisinger era continued indefinitely, Superman would have eventually come to the logical conclusion that 'Hmm - come to think of it, every person on Earth is a possible risk to my secret identity, given the right circumstances. I guess I'll just have to KILL THEM ALL!' Oh, and poor Lois. You do torment yourself so. It doesn't MATTER if your soup was good or not - the dude just ate a full saltshaker! He ain't tastin' that soup.