Yep. Just like over-domesticated fish strains, overprotected people are more likely to develop all sorts of allergies and succumb to infections. When I was a kid (before five), I ate balls of hair from under the couch, paint chips and mud. Who knows what else I ate, my memories from that time are few and far between. But as an adult, I rarely get sick, and I have only mild allergies to dairy and 'hayfever/seasonal allergies'. Immune systems need exercise, too. Not with salmonella, of course, but the vast majority of household lifeforms are useful punching bags for a developing system.
