Dr. Karl Kruszelnicki ran a science-focused radio show in the early 2000s, which led to one of his most unique experiments ever. A nurse called in wanting to know if she was contaminating the sterile room she worked in when she silently farted. Curious about the answer, Dr. Kruszelnicki vowed to find out. He worked with a microbiologist in Canberra, Australia to devise an experiment. He had a colleague fart directly onto two Petri dishes from a distance of 2 inches away. The first time, he broke wind fully clothed, and, the second time, the doctor had him take his pants down.
They let the Petri dishes sit overnight before analyzing the results. They found that the second Petri dish had grown two lumps of bacteria that are usually only found on the skin or in the gut. The first Petri dish showed nothing, which led Dr. Kruszelnicki to believe that the clothing acted as a barrier or filter. Their final deduction? The bacteria that had come from the second fart was skin bacteria from the butt cheeks, meaning that germs were only being passed when people farted without clothing on. However, he noted that the bacteria were in no way harmful, and that they were actually similar to bacteria found in yogurt.