You will definitely need to dump the fruit as I know through experience, I once had an apple which I had taken as part of a early morning flight snack, which I didn't eat. I queried it with the cabin crew as on the visa waiver form you had to tick to say you weren't bringing in any fruit and wanted to check whether one apple would be a problem or whether they meant bringing in a large quantity. They said I would probably be ok with one apple, but to declare it which I did, I then had to have all my luggage re-scanned and was made to feel like a criminal all because of one pesky apple. Had I known the trouble it would cause I would have dumped it on the plane!