Bananas are naturally high in potassium. Potassium is a mix of isotopes, including the radioactive isotope potassium-40, so bananas are slightly radioactive. The average banana emits around 14 decays per second and contains about 450 mg of potassium. Bananas can trigger a radiation alert for authorities seeking nuclear material.
Carrots, potatoes and lima beans contain some radon-226. In other words, we eat radioactive. Unbelievable!