How can I tell if my raw meat has been pre-brined/injected? I've heard that some grocery store meats (whole turkeys, ribs, etc) are sold pre-brined so as to avoid toughness. Of course in a lot of situations you'd want to start fresh and brine or inject the meat yourself.

In the US, is there any way to know based on labeling if the meat has anything added to it? Should it be on the ingredients list?

Seems like they can get away with injecting water without labeling it but I'm not sure about salt/seasoning. In particular I'm wondering about Farmer John ribs.
I always thought that the pre-brined meats are sold as being enhanced, usually followed with a percentage and what they are "enhanced" with.