A lot of EVOO isn't, but that's not your grocer's fault. Oil goes rancid, so it doesn't matter whether it's EVOO, peanut oil, or (shudder) sesame oil, mayo... It's oxidation --reaction with the air-- so I wonder if those pumps used to cap wine bottles that suck the air out would hlp prevent it. If you don't have a problem, though, it's probably not worth it to try.

Peanut allergies & generations: there's one theory that kids who've had a bunch of childhood infections are less likely to develop odd immune system reactions. I don't know why, but I can imagine the cells responsible sitting around and talking. "Wait? Hell, I'm gonna go out and KILL something!"