Don't forget the salt!!
You only need this if you are eating contaminated food and drinking contaminated fluids. If you hear of a nuclear detonation, leave the area and don't eat anything or drink anything except from sealed containers until you have decontaminated yourself and are far away from the area.
These things have been sold for use after a major nuclear bomb attack where there have been multiple nuclear bombs and there is no where to go and you have to eat what is there with you in the contaminated area. For what we are facing the best advice is leave the area, decontaminate yourself and refrain from eating until you are decontaminated.