I think my wife is too obsessed with hygiene and is overprotective of our daughter. How do I tell her to be more carefree?

I think it's just a natural mother's instinct to keep germs and bacteria away from her baby. I think I was quite a pain in the neck about it too when my son was still an infant. However, if she is over doing in, have a sit down and talk with her while watching the baby together. Is something bothering her for her to act that way? Or is she afraid that something/someone would hurt her child? Talk to her and understand her concerns and I think it would be easier for her to let go.