I was baking bread yesterday and ran out of flour. Today, as I was placing my order, another customer’s comment caught my attention. She wanted to know if the wheat had been irradiated. Unfortunately, there wasn’t a clear or conclusive answer available, so I decided it was time to learn something new. After a little sleuthing, here’s what I learned.
Humans have been preserving food since we’ve been eating food. We’ve always had some reason to need food when fresh food isn’t available. For example, preserving meat with salt before refrigerators or using canning methods to keep fresh produce available during the winter.
A “modern” method of preserving food uses radiation. According to the EPA, “food irradiation is a process that uses radiation to control pests (e.g., microbes and insects) in food and prevent spoilage.” The radiation used is very similar to the radiation used for x-rays.
According to this article, “the concept of irradiated foods first reached the public when Soviet cosmonauts complimented American astronauts on the tastiness of their irradiated steak during the 1975 Apollo-Soyuz rendezvous.” Fascinating, right?
So naturally, I was curious about what food items were permitted to be irradiated under the name of preservation. The FDA’s list as of my writing includes the following items:
It seems that spices and seasonings are most commonly preserved by irradiation methods, which was apparently approved by the FDA in the early 1980’s.
I was curious how food actually goes through the irradiation process. The dose each item receives is determined by category. This article states that low (up to 1 kGy) to medium doses (1–10 kGy) kill insects and larvae in wheat and wheat flour and destroy pathogenic bacteria and parasites. Low to medium doses also inhibit sprouting of potatoes and other foods and slow the ripening and spoilage of fruit. Higher doses (10–50 kGy) sterilize foods for a variety of uses such as for astronauts during space flight and immune- compromised hospital patients who must have bacteria-free food.”
Once the dose is determined, this article stated that, “food products to be irradiated are put on a conveyor belt which travels through a shielded chamber, with walls of 6 1/2-foot thick concrete, where the products are exposed to gamma rays.”
There seems to be quite a bit of interesting dialogue around the topic of safety. Irradiation is endorsed by the FDA, the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture (USDA).
According to several other articles I read, many scientists seemed concerned about several other effects that have been noted on irradiated food. One article summed up the specific concerns nicely: “the loss of vitamins; increased production of naturally occurring ‘aflatoxins’ (a carcinogen produced by certain fungi); creation of new chemicals or ‘radiolytic products’ in food; and the increased risk of food poisoning by radiation-resistant botulism bacteria,” as well as the long-term carcinogenic potential.
It seems commonly understood that vitamin damage/depletion from irradiation occurs. There is actually an established order because, “Not all vitamins have the same sensitivity to irradiation.” The article goes on to specify, “for water soluble vitamins, the order of sensitivity is generally: thiamin > ascorbic acid > pyridoxine > riboflavin > folic acid > cobalamin > nicotinic acid. For fat soluble vitamins, the order of sensitivity is generally: vitamin E > carotene > vitamin A > vitamin K > vitamin D. Interestingly, the article cited this information originated from the WHO.
Further areas of concern include 441 scientific studies (cited by this article). Apparently all but 5 were dismissed by the FDA despite concern about, “the possibility of creating cancer-causing chemicals in the food itself.”
So that leads me back to my loaf of bread and the wheat I ordered. My understanding is that certified organic food is not supposed to be preserved by irradiation. If you’re looking for other ways to tell if your food has been irradiated, there are a few things you can look for.
One is the “radura” symbol. There also may be a statement on the package. Irradiation is considered a “process,” which means its declaration may not be as overt as nutrition contents or allergens. Foods that have been treated with irradiation may be in bulk and therefore not labeled (like fruits and vegetables at the grocery store). They also may be served at a restaurant or as an ingredient in a multi-ingredient product (for example “spices” on an ingredient list may have been irradiated, but they are not required to be declared on a product that uses those spices).
I’ll definitely be keeping my eye out for the radura symbol, and I’m grateful that the fresh produce grown by my local farmers has not gone through the irradiation process. This has also given me much to ponder as I reflect on how abnormally long some grocery store tomatoes have seemed “ripe” on the outside and not so great on the inside, or how much faster the organic potatoes sprout than the non-organic ones.
I hope it’s given you some food for thought, too!