Question

Do bananas contain radiation?

Answer 1

You are right in that bananas contain potassium and K-40 is a naturally occurring potassium isotope AND the K-40 in an average banana does decay at a rate of about 31 ATOMS per second (half-life is > 1 billion years). This is an extremely low level of radiation and nothing to worry about. Bananas will definitely NOT cause a "nuclear winter."

Answer 2

Banana does but it contains a low amount of radiation. So low it does not affect us when we eat it