From the brief investigation I did on banana diseases, all of them just affect the plant itself (did you know that it is technically an herb?!?). There are a variety of chemical agents used in pesticides which can both leech into the skins of the fruit, and onto the boxes that they are shipped in. I am not sure how much of the chemical can leech through the banana's skin though - it's pretty thick. If you think of an apple in relation to a banana, they have much thinner skins, and would be more likely to let the chemical through the skin. That being said, the pores of the skin are small, and are made to only let certain chemicals pass through. It is always a good idea to rinse any produce before you eat it, to rid any chemicals sitting on the surface. As for the boxes, I'd pass on using them for food products until they have been treated though recycling.

I am certain that the answer is yes, especially when it comes to chemicals (e.g. pesticides). However, I doubt very much that there is anything specific to bananas, i.e. a common cold virus could hitch a ride on the skin of a banana as it could on just about anything else (and no, it could not get through the skin into the banana). I don't know of any specific pesticides either, but I do know that this *sort* of thing happens with other fruits (there was a pesticide that was sprayed on apple blossoms and got all of the way through the apple).