...and I read the thread below from Henry as well. I have gaps in my floors at home, so I can visualize this well. You fill them with caulk. First, the finish won't adhere to silicone and beads up. Try painting silicone caulk and see what I mean. Second, even if it does adhere to the silicone, as the boards expand and contract the finish gets squeezed and pulled as the silicone gives. Now you have flakes coming up off the floor. Poly can also be like dead sunburned skin. A little peel starts a chain reaction. Especially on a well travelled floor like a retail shop. Now you have a peeling floor and your silicone begins to get scuffed and chewed up, taking on a milky appearance. Try digging that out. It'll take some time.
Honestly, I'm surprised that a food establishment will be allowed to have a floor with gaps. I assumed from a local health department standpoint that there would be rules and regulations to keep food accumulating in dining areas. At least that was the way it was when I worked in a professional kitchen 10 years ago.
I think you leave the floors without caulking and seal them if you are allowed to do that.