I checked out the fed site, and it said that products like bread were allowed if they were packaged and labeled. Probably explains why some places say yes and some no.

As an aside, when we were in Carriacou I'd bought a bottle of Jack Iron Rum, and told the guy I needed a sealed bottle as customs didn't allow opened bottles. Mind you, the stuff is distilled in Trinidad, shipped in bulk to the island, and bottled in recycled bottles by the numerous rum shops (mine was a former Dewers Scotch bottle), a xerographic label taped to the bottle, and the screw cap re-tightened. So, to honor my request, he sealed the cap with transparent tape. I declared it, but no one checked, otherwise it might have been confiscated.