From a Guardian article: A study has found that a typical apple carries more than 100m bacteria. Some of these microbes are important in maintaining a healthy gut environment, or microbiome, says Prof Gabriele Berg from Graz University of Technology, Austria, one of the authors of the research.
What's the acronym for Gratz University of Teshnology? Why, it's GUT!
I was anticipating what you were going to say - and I had expected, "Maybe that's why they say, 'An apple a day keeps the doctor away.'"