If you bake a lot of sourdough bread, your hands might look like your loaves. Bacterially speaking, that is. The microbes found on bakers' hands mirror the microbes within their starters — the bubbly mix of yeast, bacteria and flour that's the soul of every loaf.
If we look at the average human hand, those bacteria and those yeasts are really quite rare — three percent maximum of fungi on the hands. On the bakers, they were in some cases up to 60 percent of the bacteria in particular on the hands. Which is to say that the hands looked more like sourdough in terms of the microbes they had more than they looked like the hands of the plumber or the professor.