Bananas actually are radioactive due to a small amount of a radioactive isotope of potassium called potassium-40. However, the amount of radiation emitted by bananas is miniscule and of no concern. However, if you still happen to have some orange fiesta ware from the early to mid 20th century, you definitely want to discontinue using it, as the glaze that makes it so vibrantly orange contains a radioactive isotope of uranium that can cause harm if the pottery is chipped and accidentally ingested