The human stomach is a force to be reckoned with. It doesn't just digest food, it protects you and keeps you from getting sick. This is because the stomach releases proteases, which kills off harmful bacteria that could injure your body. How does this work? Proteases consists of protein-digesting enzymes; it contains (amount other things) hydrochloric acid. This acid breakdown food for digestion, and it also kills the bacteria that hitches a ride into the human body via the food that we consume. This happens because hydrochloric acid is extremely corrosive (so much so, cleaning products often contain diluted hydrochloric acid).
The acid that is found in the human stomach can breakdown food in as little as 40 minutes. Unfortunately, as anyone who has ever had a stomach flu could tell you, hydrochloric acid is also rather...pungent.
So, what does it look like as your stomach breaks down food for digestion? Well, it's a little bit horrifying — and also quite impressive. In the below video, researchers ask, "What happens when you dunk a cheeseburger in concentrated hydrochloric acid?" in order to better understand how the digestion process works.