Sorry darth but it's a chemist not a biologist. The first recognised industrial disease was cancer of the scrotum - in oil industry workers who didn't was their hands before going to the loo.
Not quite right Gef. The cancer of the scrotum wasn't confined to oil industry workers and it had nothing to do with washing their hands. It was caused by continuously wearing oil soaked clothing which was rarely washed. The oil (which can be abrasive) in the clothing rubbing against the scrotum is what caused the cancer and it was common in all engineering industries.
Further to the before / after debate: my Physics teacher at school informed us that there was no need to wash your hands unless you had 'actual matter' on them, as skin is capable of eradicating 'bad' bacteria by itself.
Admittedly, this is from a woman who kept a chicken in a hamster cage.