I don't mind sharing my secrets with you guys so here goes.
For some shots I simply used a coat hanger, particularly with the Banana and Apple. Manual Focus.
Place your subject where you want it, get it in focus and take the shot.
Fruit slices by
D.J.Flynn, on Flickr
Remove the subject and take another shot at the same focal length.This ensures the background has the same depth of field.
Fruit slices by
D.J.Flynn, on Flickr
Bring both shots into PS, with the 'wire through the apple' as the bottom layer. Add a layer mask to the top layer and paint over the wire with a black brush.
THE RESULT!
Apple2 sliced by
D.J.Flynn, on Flickr
Here's a couple more, now I'm off out fruit shopping, back later with something different.
Instead of a coat hanger for the Strawberries, I used toothpicks.
Fruit slices by
D.J.Flynn, on Flickr
Fruit slices by
D.J.Flynn, on Flickr