Interesting findings in this ABC Science piece:
Washing the hands, and then using paper towels or continuous-loop cotton towels reduced the bacterial count by about 45–60 per cent. But washing, and then using a warm-air dryer actually increased the bacterial count by an average of 255 per cent.When they went looking further, the researchers found out how. The bacteria were already inside the warm-air dryers, thanks to the warm moist environment. Every single warm-air dryer they tested had high bacterial counts on the air inlet, while 97 per cent had them on the outlet nozzle surfaces as well.