Just look at what they put in what you eat in processed foods (Damn Cool Pictures).
I am not sure I believe everything 100%, but it still makes you think.
Here are the two I know to be true about castoreum:
And this one I know is correct because I had a friend who was allergic to pork.
She ended up getting sick in a hospital one day because of a stray piece of pork and they kept feeding her Jello to help her recover. She kept getting worse and worse until they realized that there was pork collagen in the Jello she was eating. Once she stopped eating Jello, she was fine.
Now, I happen to enjoy offal (stuff like tripe, tendons, etc), so it doesn’t really gross me out. What grosses me out more is that people may not know there is pork in their Jello, and the colour/texture of Jello is just so off-putting.
Even as a child, I disliked Jello.
You can see a lot more of the photos about other hidden ingredients here.