'disgust' is interesting and not necessarily rational.
Give most people a glass of water and ask them to spit in it, and then ask them to drink it. Most people don't drink it. It's their spit, it's only just come out of their mouth, so why don't they drink the water?
You won't take sealed candy from people on the street because it might be poisoned?
If the candy is sealed they could have just as easily snuck it onto a store shelf.