Hi, everyone! It bugged me that I lost the challenge because of a stupid ghost, so I decided to devise a method of displaying food while also making it ghost-proof. Many of you probably already know how to do this, but here it is.
I added a second floor to my museum. I built my doorless, windowed food display room in the middle of the second floor. Then I deleted a one square space completely around the food display room. AFAIK ghosts can't fly. The ghost has been out three times now. Each time I've had people on the same floor as the food to encourage him to wander over that way and visit. So far the food has not been eaten. Anyway, thought I would share for anyone else thinking about displaying food and keeping ghosts.