How come we didn't die from penny candy and other things?

I gave the storekeeper a nickel and pointed to the case. He reached in with his fingers and gave me two licorice sticks, two pieces of bubble gum, and a gelatinous red coin of “candy money.” Not one of them was wrapped. He dropped them in a paper bag. He didn’t wash his hands. I ate them with the same bare fingers I’d been out in the world with all day, in trees and fields and digging in the dirt and playing on schoolyard jungle gyms.

How come we didn’t die of naked-candy poisoning, money-touching poisoning, unwashed-hands poisoning, and everything else? How come we shared bites of candy, picked things up off the ground, picked unsprayed green fruit from trees, drank from each other’s Coke bottles, and survived? Never mind that we’d all go to jail now for all this felonious germ-sharing, how come we grew up healthy and never seemed to suffer any ill effects from this flagrant failure to exhibit microbophobia?