Radioactive contamination of food is a complex topic. This article tries to explain some basics in a simple way and clears up some misunderstandings in order to have better food safety, both in times of peace and in case of an event.

Radioactivity consists of three components, a high-energy wave (gamma radiation) and particle radiation (alpha and beta radiation). We will not go into more detail here on the different types, how to shield from them and what damage they do, just acknowledge that in terms of food (and fluid) intake, the weak alpha particles (in the body) are the most dangerous.
 

It is important to remember that food in its natural form is NOT radioactive, it cannot become radioactive from e.g. cosmic radiation or due to natural soil conditions. If, on the other hand, an area has been exposed to man-made radioactive substances, then it accumulates in plants or animals, as a result of accidents and their aftermath (Fukushima, 2011 and Chernobyl 1986), or as a result of atomic bomb tests in the 1960s (Stäger et al, 2023).

All food (like everything else in existence in our dimension) consists of chemical components. Some of these substances are more susceptible to becoming radioactive. The most important ones of these are Strontium, Iodine, Cesium and Plutonium. We will come back to that later.
 

Radioactive Materials Derived from Nuclear Accidents. Ministry of the Environment, Government of Japan, 2013

Substances that have become radioactive and are now in or on the food are then eaten, digested, distributed in the body and accumulate in organs that are particularly exposed to it. There, they will lead to cell change / cancer in the long term and cell death and organ failure if they are strong enough.
 

Solutions: To protect yourself from this process, you have different options:

1. Only eat food that cannot have been exposed to alpha particle radiation. If you are in an area where an accident or other radioactive / nuclear incident has occurred, then only eat canned food, freeze-dried meals, or food that is in a tight packaging that can be washed before use.
 

2. Wait long enough for the radioactivity in the substance to have been reduced enough for it to fall below a dangerous level (ref the so-called half-life).
 

3. Saturate the thyroid gland which is prone to accumulation of radioactive iodide with non-radioactive iodide in the form of tablets.
 

4. Measure the radioactivity of food (vegetables, fruit, mushrooms, but also animal products such as milk and the meat from animals themselves) and then decide based on a limit value whether the food is safe enough.

The first measure, washing and eating canned food, is easy to carry out in the short term if you have access to such foods. The second measure, to wait, is not practical since it will take between 7 days and 20 years for ONE halving of the substance.
 

The third point, potassium iodide tablets are available in peacetime in pharmacies without a prescription and, if an event occurs are supposed to be distributed by the authorities and to a greater or lesser extent be available to the entire population. Reality differs from theory.
 

Children and adults under the age of 40 as well as pregnant women have the greatest effect of high-dose iodide. So even though the municipality has a responsibility for emergency preparedness and preparedness-minded individuals and families take care of their preparedness by investing in gas masks and iodide tablets, the overall effect is limited: The tablets do not protect "against radiation" as so many people believe, but simply reduce the risk of cancer in one of the body's many organs (the thyroid gland) against the uptake of one radioactive substance, iodide (Jaworska, 2007).

As always: We strongly suggest that you follow the authorities' recommendations and encourage you, dear reader, to make up your own mind as to whether your personal safety and health is being taken care of well enough. This requires knowledge.
 

So to the last and most important solution, measuring radioactivity. This is in its core a bit complex:

Most cheap, generally available measuring devices for radioactivity today measure gamma radiation (Geiger counter). When it comes to sensitive devices, these are perfectly fine for judging whether an area is dangerous for people to stay in and how long you can stay in an area before you have to seek cover again (dosimeter).

But such devices are far too insensitive to measure particle radiation from the weakly energetic alpha particles. In other words, holding a cold-war Geiger counter against the mushroom that you have collected in the forest will, in the best case, lead to measuring of the background radiation in the area only.
 

There are measuring devices for alpha radiation, but in order for them to be affordable for most people, they are either former military devices that lack a calibration source (since it is radioactive) and one must have knowledge of how to calibrate such devices oneself, or one can buy affordable, civilian devices and apply the physics knowledge you have gained in highschool or acquired afterwards. It also involves a lot of tinkering with lead to create a tight container that you can put both the device and the food source in. So something that is NOT applicable, neither for lay people nor in a crisis situation, where you may have been given responsibility for deciding whether a number of foods are safe to eat for people.

An alternative that has emerged in the last year and which is quite fascinating from a technical perspective is gamma spectroscopy: A small, inexpensive device measures gamma radiation in an area and shows this not only as ONE numerical value, but in the form of a diagram that tells tell us what type of radiation is near the device.
 

The operation is intuitive and the device can be used by itself / stand-alone, connected to mobile phone and app, or your computer.

Without getting too technical in this article: For anyone wondering how a device that ONLY can measure gamma radiation can detect alpha / beta particle radiation as well, this has to do with decay: Alpha radiation is released from decay from gamma radiation and vice versa . The device / software is so "intelligent" that it understands that it is dealing with a decay product and will thus be able to analyze such particle radiation too!

In our example, we're going to find out if chanterelle (a mushroom known to accumulate radioactivity) is safe to eat. With a click and waiting for about 30 minutes, we have determined the background radiation in the room, which is important for subtracting it from the diagram we get when we measure the mushroom. We then measure the mushrooms for 30 minutes. Remember that the test has deliberately been carried out as in-situ and unscientifically to simulate real events.
 

As previously mentioned, certain substances are particularly dangerous when they accumulate in the body. In the image example further up, we have chosen Cesium 137. This substance will affect the whole body. We can see that the level is NOT elevated here. At the same time, the analysis of the entire spectrogram shows that the total load of THIS mushroom picked in the deep forests of Eastern Norway is NOT dangerous to eat from a radioactive point of view.
 

As always: The article is to be considered a personal opinion with no guarantee of completeness or correctness. I will always make sure to use the best possible sources. The use of the recommendations is the responsibility of the reader. Read the disclaimer here and use common sense. Thanks.
 

If you want to strengthen the preparedness of your family, workplace or municipality, get in touch!