Silly examples don't work. Food preparation for an unsuspecting public versus the legal right of a business to run their operation as they see fit by allowing a legal activity on the premises. Until you make smoking illegal, you have no right to insist on enforcing the nanny-state on a business.
Regardless, if there were no health inspectors restaurants would be open to law suits if they prepare anything that hurt unsuspecting patrons. As corrupt as many so-called inspectors are you may have a good point.
Smoking is hardly an unknown activity when you walk through the door. One wonders why in the world you would even want to go inside a business that has smoking? Why not just not go there? Is that so hard for you to understand? Are you incapable of making such a decision, meaning which places to patronize and which not?
This is what the Constitution envisioned, not smothering regulations. You screw up, you pay the piper, not a bunch of petty bureaucrats eating out our substance.