The celebrity PoopReport might want to interview would be Dr. Chuck Gerba Ph.D, a microbiologist. I think he is at the University of Arizona. He has tested germ counts in various parts of public restrooms and private homes and noted the dirtiest parts of each. He was checking for germs in a public restroom and a police officer interrogated him, thinking he was a pervert. When Gerba insisted that he was a scientist doing serious research, the cop snarled, 'Yeah. I bust scientists in here all the time!'
I've located some summaries of Dr. Gerba's work, and an interview with him --
here and
here.