I didn't know anyone was using it as a descriptor like that, but in that context it seems to mean eating foods that have been around long enough to prove they h

I didn't know anyone was using it as a descriptor like that, but in that context it seems to mean eating foods that have been around long enough to prove they have staying power and aren't harmful over any measurable time scale, or somesuch. Not sure I agree, but I sure understand the motive.