We ate more than half the food in the bag. When I pulled out another burger to eat I noticed that there was a full blown glove wrapped with the burger.
I understand how gross this must make you feel.
Can you sue? You can sue anyone for anything, but that doesn't mean you can win. I imagine you'll have a hard time finding a lawyer to bring a claim for this unless you can prove you were injured. Injury might be a long term problem from choking on the glove, or development of COVID if you can prove that you got COVID from this glove and not somewhere else. But unfortunately proving this glove caused an injury for you might be difficult. If you're willing to go to the expense, and if you still have the glove, you might quickly find an expert to test the glove for COVID (this may cost thousands). COVID can stay on surfaces for days, but unless you have the glove tested immediately you may lose evidence that the glove was contaminated.
Similarly, if a drunk dude drives through my neighborhood at 100 mph I might be really mad. But unless he hits someone, even though he committed multiple crimes, there likely isn't a good personal injury case.