I heard of this before. It's still pretty disgusting. I say just let kids be kids and they will develop normal and healthy. When parents micro-manage a kid's behavior, douse them with hand sanitizer or constantly Lysol everything in the house, they will grow up sickly and paranoid.

Just my 2 cents.

I agree, eating boogers, dirt, and food that dropped on the ground but still within the 5 sec rule all helps to build a child's immune system

Agree! ESP the 5 second rule!! It's the Rule of the land when it comes to food.

"Let kids be kids"
Here is a photo Grandma and her kids circa 1930. The tallest is my Mom. Notice no shoes anywhere to be seen? No rubber slippers back then either.
As I recall they could only wear their shoes to church and maybe to school. Mom lived to be 85.... I should be so lucky.

Advice to new parents and future parents:

 Let your kids play and get dirty. It won't kill them. It will make them stronger and tougher. Let them do fun stuff like catch bugs, play with fire, shoot at stuff, make home-made weapons, go swimming, camping, and hiking. Kids grow up too quickly, but they will have good memories of childhood.