Radioactivity in food

In our glasses and on our plates ...

The very acts of breathing and walking around make it impossible for us to escape radioactivity. We also regularly come into contact with radiations when we eat: all foodstuffs are slightly radioactive due to their content of carbon 14 and potassium 40 – radioisotopes that are present wherever regular carbon and potassium can be found.

The spring water that we drink is also radioactive. Before bursting out of the ground it has dissolved various mineral salts from its underground path, including a large variety of radioisotopes. The most radioactive waters come from areas with granite or volcanic rocks, where uranium, thorium and their descendants are present in the ground. The exposure levels here, however, vary wildly.

In the United States, the average activity of household drinking water is of 18.5 Bq/litre, which corresponds to a truly inconsequential risk given the tiny value of the becquerel. Today, legislation places upper bounds on the activities food and drink can have – owing to our ignorance about the effects of low doses of radioactivity, caution is the watchword.

One of the reproaches made to the French radioprotection authorities after the Chernobyl accident was that they had not prevented the distribution of products whose activities surpassed the recommended limits. These ‘high’ levels were probably too small to have had an effect in any case, but the perceived lack of administrative transparency and the feeling that dangers were being hidden all undermined the trust the public had in the experts. The shock waves of this psychological disaster are still reverberating through modern society.

Much like the legal limitations on alcohol consumption prior to driving, the limits on radiation exposure have been steadily decreasing over the past fifteen years. As always, the risks are taken overly seriously in order to keep public safety as high as possible. Paradoxically, however, the exaggeration of these risks has led to more worry and unease among the general public as to the dangers of radioactivity and ionising radiations.



An other example of these baseless worries is the concern which surrounds the irradiation of food. Irradiation is a highly effective method of sterilization which does not affect taste and, according to the WHO, leaves no radioactive traces. Pepper and various spices, for instance, which are very easily contaminated by dangerous bacteria, were until recently regularly exposed to sterilizing radiation. New regulations, however, required ‘sterilization by ionisation’ to be written on the packaging, which prompted several companies to back away from predicted panic and revert to less effective, more dangerous methods.



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