Tracking dirt indoors: not a health hazard

https://www.heraldtribune.com/entertainmentlife/20190910/tracking-dirt-indoors-not-health-hazard

But in the hierarchy of potential health hazards at home, bacteria-caked shoes rank comparatively low, according to Donald W. Schaffner, a food microbiologist at Rutgers University in New Jersey.

Hi everyone ! 
A Vietnamese friend of mine told me she is shocked when people come home without taking their shoes off.Most of us take their shoes off to be more comfortable. We don’t want to track  dirt across clean carpets or floors, especially because we think that bad bacteria cling to our shoes.
Reading this text, I can see that it is not that bad because contaminated shoes are unlikely to make us sick.