what is this meat?

Sometimes I wonder what happens to pets on death row after they have been put down. What exactly happens once dead?

I've never seen a real pet cemetery in life, other than that movie of the same name.

And also what happens to unclaimed people, without someone with power of attorney

Like what happens? they don't have money for a burial, and cremation cost money.

So like is our meat supply safe from contamination

And can anyone guarantee me what I buy is what it is labeled and only that?