Can onions absorb bacteria from sick people?

take it to the vet
small amounts such as that may make it sick but a vet is the best source of advice
while onions are toxic there are many animals that can handle the vegie in small amounts

yes , of course you do, any red blooded american knows that.

Onions take back in toxins

hi Patty.

Can Cut onion be used next day? Using Precut Onions. Chopped or sliced onions, properly stored in the refrigerator,will keep for seven to 10 days, according to the National Onion Association. If, however, the onions are mushy or slimy or if they have a cloudy liquid around them, toss them, MacDonald cautions.

Is It Dangerous to Cut Onions a Day Before Cooking Them ...

https://www.livestrong.com/.../500096-is-it-dangerous-to-cut-onions-try-to-use-them-to-... Search for: Can Cut onion be used next day?

Can you save an onion after you cut it?A: Chopped or sliced onions can be stored in a sealed container in your refrigerator at the proper temperature of 40°F or below for 7 to 10 days (Source: USDA). For pre-cut fresh or frozen products, always use and follow manufactures "use by" dates.FAQs - The National Onion Associationhttps://www.onions-usa.org/faqsSearch for: Can you save an onion after you cut it?

you can read up more at this link.

Is it dangerous to cut up an onion one day and use it to cook with the...

Cut onions absorb bacteria. Cut one and watch. In a few hours you will see it becoming black.

http://www.bestfoodfacts.org/food-for-thought/leftover-onion

Hello.

You can just dunk the onions in Iced water for 30 seconds, or even boiling water, this will change the texture of the onion. Next thing to do is use a very sharp knife, start out by cutting the roof, it'll eventually release the gas. That's it.

1.) get a stick of butter and cut a slab off.
2.)Rub the cut section of the leftover onion with the butter. Soften the butter ever so slightly if you need to, by letting it sit at room temperature for a few minutes.
3.) Place the onion on foil and wrap it tight.
4.) then place in a tupperware dish to keep you fridge from smelling like onion
5.)Store the onion in the refrigerator, the butter will act as a barrier and prevent the outside air from drying out your onion.

Here is another good reference http://www.ehow.com/how_8111893_store-cut-onions-refrigerator.html

I'll let you in on a little chef secret: White onion! Cut an onion in half, stab the round part with a fork. Heat up the pan or griddle and rub the onion across it. This will help remove all the gunk that gets stuck there.