How are bull frogs able to eat scorpions and spiders and not get stung or bitten in the mouth or stomach?

I just saw a video of bull frogs swallowing whole BIG spiders and scorpions. I thought the spider’s fangs would ruin the frog’s whole day or kill him. I also thought that stinger on the scorpion would totally stop the bull frog from living? How can they do this?

When a frog catches its prey, it quickly bites, stunning its prey with the bite. The frog then closes its mouth and may crush a softbodied prey in the process. The frog will also make sure that its prey is not moving, by holding it between the roof of the mouth and the tongue, before swallowing. While the prey is inside the mouth, the frog secrets a large amount of digestive enzymes onto its prey to help it go down its gut smoothly. After having been stunned, crushed and coated with digestive enzyme, a spider or scorpion would have no chance to sting or bite.