OCD rituals are done due to fear. If she was afraid she may harm her child, she could have cleaned religiously to get rid of her thoughts. I used to hide knives because seeing them would trigger a thought. Out of sight, out of mind. It was silly but it helped me get rid of the thoughts that eventually disappeared for good.
Possibly, cleaning was her way to get rid of them OR you're right, a fear of germs. But I'm not feeling like she has OCD here. No one with OCD cleans to the point where they refuse to feed their children.
I'm leaning towards a psychotic break or another mental illness. That is, if what her husband said was true of course. There are always three sides to the story, his, hers and the truth.