This. I know someone who's worked in that industry, and they've told me that a lot of the chemicals (ones that aren't required to be labeled) in certain types of shredded cheese and pizzas (used to keep the shape of the shredded cheese) are known to be carcinogenic by those who manufacture them and have a long list of untested, unregulated chemicals that they switch to when the FDA bans whatever they're using currently.

Shredding cheese yourself also tastes better.