Yes they did a study and people who are too clean have more illness and allergies.I am on community well. I think ecoli is one of the things we had natural resistance to but since we sterilize our world we lost our tolerances. Chicken eggs have salmonella so we should all be sick constantly. Honestly I've stopped cleaning my coffee cup and have used the same fork in my work truck for months without washing. And I've never gone this long without being sick.