I know that in Latin, the word for "evil" or "bad" is also the word for "apple".
Malus.
I think that may be where Christians got the whole "the evil* fruit was an apple."
In Islam, it's generally identified as a banana.
I must admit, due to my Christian heritage, I want to laugh at that, but it's no less valid an interpretation than the freaking apple.
Then again, when I was a kid, I remember watching a cartoon movie of the Adam and Eve story where the evil fruit was basically a rainbow colored apple-shaped fruit. I think. It was weird.
*I know that it's not actually the "evil fruit", I just didn't want to type out "Fruit of the Knowledge of Good and Evil"