Vinegar is a good disinfectant. You can find a variety of recipes by googling "non-toxic home, cleaners," or similar key phrases. I don't have hardwood floors, but if I did, I think I'd also add a splash of Citra-solv, which is made from orange peels with no toxic solvents added. (http://www.citrasolv.com/products.shtml)
Be aware that "killing" bacteria happens naturally, without chemicals or any effort on our part – most of them will die as they dry out only an hour or two after landing on most surfaces. Mold spores will live somewhat longer, but they won't generally be a problem in open areas with decent ventilation.
So even if a surface looks dirty, there are probably few if any living bacteria on it unless a person or a pet was recently in contact with it. We all have huge societies of bacteria on our skin, most of which are helpful and outcompete the nasties. And of course, new bacteria can be deposited just moments after you've cleaned the floor.
The obsession with killing bacteria that so many of us are burdened with is the result of decades of very effective advertising.