Exposing food or packaging to gamma rays, x-rays, or electron beams is called irradiation. It’s used in conventional food production to destroy pathogens or spoilage organisms, destroy insects, delay sprouting or ripening, and to sterilize food for long storage. I note conventional because irradiation is prohibited in order to get organic certification in the US, EU, Australia, and New Zealand (not an exhaustive list). This topic always leads into a lot of questions.
If food is irradiated, will I be exposed to radiation? No. It’s a method, not an additive. The treated food is not radioactive and neither are you after eating it.
Can I tell if food is irradiated? Sometimes. Not by sight, taste, or texture. Irradiation causes very little perceptible difference in treated products. You may be able to tell by labeling. Anything organic is by definition not irradiated. Specific foods and ingredients are approved by the FDA to be treated with radiation, and each type has a maximum dose. Food treated in this way has to carry the Radura symbol:
But there’s an exception. When irradiation is used on an ingredient that goes into a product, the final package doesn’t have to carry the symbol. The most common example of this is irradiated spices used in packaged foods.
Radura is an international symbol. Australia and New Zealand use it, but the EU doesn’t. Instead, they require phrasing on the package that indicates radiation has been used. And in the EU irradiated ingredients in packaged food must be identified.
What else is irradiation used for? It can be used to sterilize medical and dental equipment, take x-rays, perform carbon dating, clean pollutants from coal power, and treat cancer.
What are the downsides to irradiation? It can cause nutrient destruction, especially B vitamins, though this is true of any preservation method, even pasteurization. It also costs more than heat treatment and prevents signs of spoilage so consumers can’t detect rotting food.
Some of the most compelling cases against irradiation have nothing to do with food safety. There are many beneficial compounds in food that we can’t identify, so we can’t identify the effect of irradiation on them. Some consumers are opposed to increasing our use of nuclear power or fear that the use of irradiation will lead to a false sense of security in the food supply. Whether it’s “safe” or not depends on how you look at food and how comfortable you are with the technology.
If you are trying to avoid irradiated food, you can buy USDA Organic. Otherwise, there’s not a good way to know whether the ingredients have been irradiated, unless stated by the manufacturer.
Update: You can read more on other methods prohibited in organic food by reading about genetic engineering and biosolids.