Given the fact that both Mehadrin and Non-Mehadrin exist, what are foods that can be safely eaten in non-mehadrin places? I.e. they would not be problemaic.
(also, assuming Shemittah is not a problem)
Edit: Sorry for not being clear. I meant assuming the worst possible situation (i.e. the stuff that are absolutely kosher with minimal hechsher). Or to put it another way: stuff that don't have any "questionable" problems - only "universal" problems.
Obviously stuff that never need a hechsher (e.g. water) would be included in this category. But I'd prefer those stuff that are normally non-kosher without any Hechsher, but by having just a minimal standard of Hechsher, everyone would eat it.
If such things do not exist, then that would be a valid (although, disappointing) answer too.