My only thought is about sanitation simply because I am sure that they are covered with bacteria
(I remember in micro-biology my prof once made a comment about eating orange rind when you feel a sore throat coming on because the lactobacillus on the rind would out compete strep and keep you from getting strep throat. Apparently it's a similar strain to what we have in our throat or something - course he could also have been full of crap or, more likely, I was drunk and mis-heard...)