Bananas do have radiation, and they are discolored ionizing radiation. But there is no need to panic at all, because all talk of radiation hazards out of dose is unscientific. The radiation of bananas is related to the potassium content. Potassium is not guilty, but Potassium has a sibling, Potassium-40 (40k), which is an isotope of potassium and radioactive, and is one of the main sources of natural nuclear radiation in the human body, which means that potassium-40 causes ionizing radiation. The radiation of bananas is derived from this radioactive element potassium-40. Because the potassium content in bananas is relatively rich in fruits, the potassium-40 content is relatively higher. (via Popular Science China)
Source: Guangdong 12320