Onions keep bacteria away?!?

I recently came across something saying that you shouldn't use half an onion and then put the rest back in your fridge because it will collect bacteria.    I had no idea about this.  I have never been a big onion fan so I don't use them alot.    Recently I have gotten a ton of onions from our local co-op so I have a whole drawer in my fridge full of them. I have been trying to use them more in my dinners and new foods I'm making.  I like the flavor they add I just dont like the crunch if they aren't cooked.
Anyways so I started to research this onion thing out and sure enough there is a lot of info that says don't put an onion back in the fridge half used. It will make you sick.   I remembered hearing that way back in the day when the black plague was going around they put an open onion out and it turned black because it absorbed the disease.   I remember my mom putting a cut onion in a nylon and wrapping it around her neck when she had a sore thoat to help with it.



I started to put a cut onion out on my kitchen counter to see if it will help us this winter.  We are doing a lot of new preventative stuff this winter to try to not get sick as much.  We are eating kefir daily,  drinking green smoothies, and drinking our minerals.   We haven't gotten sick this year yet.   It might be because its a mild year but we will see.  I believe its helping for sure.  I have had a start of a sore throat a few times but it never gets past just the start of a sore throat.   So I figured leaving an onion out can't hurt.

I also started to read up on more onion healing powers.  You can cut an onion and put it in your sock at the bottom of your foot and it will clean your blood and kills bacteria and viruses.   I think its worth a try.  It could all be a myth who knows.  What do you think?