Well, don’t eat the tomato leaves for one. If you compare the mass of undried tobacco leaves to a similar amount of food, I would guess similar exposures. I would also guess that the fruit contains more water, therefore a slightly less concentration of radiation.

It’s also about the system, lungs vs digestion. Digestion has been dealing with natural radiation for longer than we have been smoking.

Good question!

I also want to point out things like strawberries are irradiated on purpose to extend shelf life, not the same thing as radionuclides in the food, but a nice example of radiation protecting the food supply and preventing quick spoilage.

Edit: I think all fertilizers are the same, mostly from petrochemical stock. Nothing separating tobacco and food fertilizer.