Natural Radioactivity in Food
- Some foods contain trace amounts of naturally-occurring radionuclides.
- Bananas and Brazil nuts are the most well known examples of foods that contain radioactivity.
Naturally-occurring radionuclides such as potassium, carbon, radium and their decay products are found in some foods. Because the amount of radiation is very small, these foods do not pose a radiation risk.
About Natural Radioactivity in Food
Some foods contain small amounts of radioactive elements. Food can gain this radioactivity in a few ways:
- Uptake: roots of plants take in radionuclides from the soil.
- Deposition: radioactive particles in the air settle onto crops.
- Bioaccumulation: radionuclides accumulate in animals that ingest plants, feed, or water containing radioactive material.
The most well known examples of naturally-occurring radionuclides in foods are bananas and Brazil nuts. Bananas have naturally high-levels of potassium and a small fraction of all potassium is radioactive. Each banana can emit .01 millirem (0.1 microsieverts) of radiation. This is a very small amount of radiation. To put that in context, you would need to eat about 100 bananas to receive the same amount of radiation exposure as you get each day in United States from natural radiation in the environment. Like bananas, Brazil nuts contain potassium, but they also contain a small amount of radium that is taken up from the soil in which they are grown.
Natural radiation in food should not be confused with food irradiation. Food irradiation is a process that uses ionizing radiation to prevent foodborne illness (“food poisoning”) and food spoilage. Food is passed through a radiation beam–like a large flashlight–to kill bacteria, molds and other pests in food. The irradiated food does not come into contact with radioactive materials, and food irradiation does not make food radioactive. Learn more about Food Irradiation.
In the case of a radiological event, there may be situations in which an animal ingests materials that contain radioactivity. For example, if radioactive materials are found in water, some fish may ingest them, which, in turn, could be eaten by a human as part of their diet. It’s important to note that, in the case of a radiological event, there will be guidance to the public about food restrictions if needed.
To ensure the protection of the public, the U.S. Food and Drug Administration (FDA) tests food in the United States for contaminants, including radiation, and sets strict limits and restrictions on foods imported from other countries.
What You Can Do
Natural radiation in food does not require any special actions because the radiation levels are extremely low.
- Follow guidance. In the case of a radiological event, always follow guidance from public officials regarding food or water restrictions.