Money circulates everywhere and people with all manner of dirt touch it. Apart from containing bacteria, research has shown that money also contains traces of cocaine in addition to other dirt. Most people are careful about washing their hands after handling dirt or going to the washroom. They are even wary of someone who touches their food with dirty hands.
However, when it gets to the cashier who is handling their food order, they do not raise an issue. The truth is that the cashier may be harboring more germs than the dirty gardener.