Irradiation: Is Your Food Toxic?

How concerned should we be about the popular arguments against irradiated food?

by Brian Dunning

Filed under Conspiracies

Skeptoid #61
August 14, 2007
Podcast transcript | Listen | Subscribe
Also available in Chinese

The Radura logo indicates food that has been irradiated.

Today we're going to critically examine a mysterious green logo on the side of a food container in the supermarket. Many people believe this means the food is radioactive or poisonous. Some trust that it's simply sterilized. Which is true?

My grandmother went to her grave with the firm belief that eating food that had been warmed in a microwave would give you cancer. The similarities between the terms "microwave radiation" and "radiation poisoning" were all she needed to form this opinion. And, unfortunately, hers was no less rigorous than the process most people follow to form opinions about technologies or methods that they don't thoroughly understand. I offer most Americans' opinion of nuclear energy as a perfect example: Chernobyl = danger = nuclear reactors are fundamentally bad. Yet, how many of them can tell you anything about the closed fuel cycle reactors being designed today? Ever since the aftermath of Hiroshima, there has probably never been any word that incites so much fear as radiation.

Simply put, irradiation is the process of blasting food with a shot of ionizing radiation, killing any microbes that would contribute to the food going bad sooner than it needs to. Bacteria, viruses, and everything else are all sterilized by the radiation. Ionizing radiation is used because it's high energy, and is extremely dangerous to living tissue. Three types of radiation are used: high intensity x-rays, which are high energy and penetrating; gamma decay, which is really high energy and does great damage, and consists of electromagnetic radiation in the form of photons; and beta decay, which consists of electrons that are too big and slow to do much by themselves, and so they need to be accelerated into a high energy state at nearly the speed of light. All three types have different characteristics in terms of how far they penetrate and how long an exposure is required, so different types are used for irradiating different foods. Whatever the method, the food coming out the other end — be it bread, milk, meat, fruit, or cheese — is absolutely sterile and, if properly sealed, will last longer on your shelf than virtually anything else in the supermarket.

How is irradiation such an effective killer? The high energy of ionizing radiation creates ionization events within the cells of tissue that it strikes. These ionization events result in chemical and even some nuclear reactions among the affected molecules. When this happens in DNA, it causes damage that, if the cell survives, can become cancer. At higher levels, sufficient damage is done to the cell that it's almost always killed outright. Guaranteed no salmonella or E. coli.

Irradiation is a cheaper way to bring safer food to the market. It's common in Europe, where refrigeration infrastructure has historically not been so great, but it's rare in the United States. The circular green logo along with the words "Treated with irradiation" are so terrifying to much of the American public that the process has been put virtually out of business. Most Americans would prefer to accept a few E. coli deaths than have their food exposed to a sterilization procedure that involves nuclear physics.

At this point in the podcast, some of you are tuning out and saying "Oh, there he goes again, towing the line of his corporate paymasters, saying whatever Halliburton is paying him to say, and talking down to people who question authority." Questioning authority is wonderful, and more people should do it. Unfortunately, most of those who claim to question authority are really just rejecting authority, for the sake of doing so. To truly question something, you have to listen, learn, and analyze.

During the anthrax scare of 2001, the US Postal Service had a lesson in analyzing. As an emergency measure, they contrived to irradiate the mail, as this would effectively kill any anthrax that anyone might be sending. Well, apparently they turned up the volume too high. They killed the anthrax, all right, but they also nuked the hell out of a lot of mail. Some stationery darkened horribly. Stamps were ruined, to the dismay of collectors. Photographic film was destroyed. Plans to irradiate all mail eroded, and now only mail to certain government offices gets this treatment. Apparently, you can overnuke stuff. Don't tell my paymasters I said this, but irradiation can be done wrong, and can have disastrous results.

Critics have pointed out that new, unexpected chemicals can be formed during irradiation, and this is true. Ionization is a chemical reaction. However, cooking, and most other food preparation techniques, cause the formation of new chemicals in dramatically higher concentrations, and this has never posed a problem. Every test ever done has found irradiated food to be safe.

But that doesn't mean they're always good. Some foods don't tolerate irradiation well. Some foods, most notably romaine lettuce, can smell bad, taste funny, or have their texture affected if they get overnuked. This is not a health concern, it's a culinary problem. The trick is to find the right dosage to kill any organisms and yet not affect the food. Almost all foods tolerate irradiation with no noticeable effects, but for some, the food gets ruined at doses too low to effectively sterilize it, and so these foods are not candidates for irradiation. For any food you see bearing the irradiation logo, you can be sure that it's been tested and its quality has been found to be unaffected by the dosage used. Not that this will satisfy consumers.

You see, a principal misconception held by many opponents of food irradiation is that the process of applying radiation leaves the food radioactive. This is completely false. This would be analogous to turning off the light in a room, and expecting the room to be residually contaminated with light radiation and still glowing. Obviously, this isn't what happens. Once the source of the radiation is removed or deactivated, there is no more radiation. It's like turning off a light. Food that's been irradiated is not radioactive.

Does this mean that you can take a fish fillet and set it outside your nuclear bomb shelter, let it marinate in the radiation, then bring it back inside and enjoy a healthy meal? No. In this case, heavy radioactive elements in the fallout dust would contaminate the fillet. When you brought it back inside, you'd bring in radioactive dust along with it, and you'll all get fried. The irradiated fillet won't hurt you, but the heavy radioactive metals sitting on its surface, still emitting particles, will. Food irradiation, and for that matter microwaving as well, does not place radioactive material onto the food. The food is placed in the radiation field, and then it's removed. Run a Geiger counter over it, and it shows zero. Food that's been irradiated is not radioactive.

Nobody has ever been sickened or harmed in any way by eating properly irradiated food, despite a few untrue claims made by the Sierra Club and others. However, many people die or catch severe bacterial infections from eating food that is not irradiated. Next time we have an E. coli breakout, step up to the plate and point out the benefits of irradiation. When lives are on the line, we should use every means at our disposal to properly sanitize our food supply.

Tip Skeptoid $2/mo $5/mo $10/mo One time

And also use every means at our disposal to get Halliburton to finally send me my check.

Brian Dunning

© 2007 Skeptoid Media Copyright information

References & Further Reading

FDA. "Irradiation in the Production, Processing and Handling of Food." Department of Health and Human Services, United States Food and Drug Administration. 3 Dec. 1997, Volume 62, Number 23: 64107-64121.

Morrison, R.M., T. Roberts, T., L. Witucki, L. "Irradiation of U.S. Poultry—Benefits, Costs, and Export Potential." Food Review. 1 Oct. 1992, Volume 15, Number 3: 16-21.

Osterholm, M., Norgan, A. "The Role of Irradiation in Food Safety." The New England Journal of Medicine. 29 Apr. 2004, Volume 350, Number 1: 1898-1901.

Roberts, T. "Microbial Pathogens in Raw Pork, Chicken, and Beef: Benefit Estimates for Control Using Irradiation." American Journal of Agricultural Economics. 1 Dec. 1985, Vol. 67, No. 5: 957-965.

Satin, M. Food Irradiation A Guidebook (First Edition). Lancaster, USA: Technomic Publishing Co., Inc., 1993. 3-25, 98-99.

Wilkinson, V. M., Gould, G. W. Food irradiation: a reference guide. Cambridge, England: Woodhead Publishing Limited, 1996. 1-177.

Reference this article:
Dunning, B. "Irradiation: Is Your Food Toxic?" Skeptoid Podcast. Skeptoid Media, 14 Aug 2007. Web. 13 Oct 2015. <>


10 most recent comments | Show all 37 comments

you call a rigid class structure "peace" Illy

Rather depends which side of the great divide you are on. However I beg to point out I am proposing reform RATHER than a violence that is increasingly inevitable

As to Tom

No way he's doing my shopping

phi, sydney
May 4, 2011 6:45pm

I think that we should get back to the great benefits of science as its applied to preserving fresh foods.

I see from above, a number of wishful thinking posts when it comes to food sales and they just dont pan out. Each has its good points and each has some woeful claims.

Some, food types can and do benefit from gamma or x-ray sterilisation. Any notion to the contrary is pure wishful thinking.

Gamma sterilisation requires a radioactive source, X ray sterilisation requires an x-ray generating system.

A gamma ray of energy nkeV is exactly the same thing as an x-ray of nkeV. The only difference is the means by which the photon is generated.

So is irradiation bad? It depends if there are processes that produce a a food spoiling effect during radiation or the level of toxins from breakdown of pathogens on or within the foods is excessive to known standards.

Is irradiation of food good? So far the food types irradiated for commerce have not had a deleterious effect that is predicted or known.

Given that that is a far greater standard that is applied to junk organic philosophy, I am quite happy to know that the very little irradiated food in my diet is safe.

Now as to the entire blither and claim marketing of the above four posts, the food from local produces in certain regions is great because it is unique to the region. No more no less.

The tomatoes, greens or fish in Sydney markets is no better or worse than in sicily. Subjectivity!

Henk V, Sydney Australia
August 31, 2011 11:20pm

The following review controverts your stance:

Bob, Seattle, WA
January 31, 2013 10:07pm

Bob, could you just give us a prasae of the abstract? Maybe you didnt read the article at all.

Lots of folk post lookey sees from web sites they read without reading the abstract at least.

Somebody did it with an acupuncture blurb not so long ago..264 almost junk articles referred to in the blurb..

Genius doesnt men you look things up...but it helps.

Mud, Pho s Brewery NSW, Oz
March 27, 2013 8:08am

Bob, it's no good linking to a source that's behind a pay wall so no one without subscription can read it.

Michael, Denver, CO USA
May 7, 2013 6:32pm

Having qualified as a Health Physics professional and gathering experience in nuclear power production and food/medical supplies irradiation.. i can tell you that a lot of research has been done in identifying the amount of ionising radiation to apply when dealing with foodstuffs - you are right in saying that an unwarranted bombardment of radiation will lead to "taste" changes - this indicates an underlying problem that the foodstuff/materials of manufacture itself can be damaged and the products of this damage cause biological effects if ingested .. Research is constantly ongoing on this and the amount of radiation (Rads/Grays) is modified to be optimal..

Ian F, Christchurch NZ
May 8, 2013 3:30pm

Brian, it is not the first time that you used to describe irradiation of an object by using a light in the room analogy. I am not saying that it is completely wrong, but there is a phosphorescent materials that will glow after been subjected to a light source. It may sound confusing to some people that experienced this phenomena (toys, watches covered with phosphor).
Any way, I am a big fan of your podcast.


Konstantin, Melbourne,AU
June 19, 2013 4:28am

The EM light source analogy holds for low energy EM radiation to high energy EM radiation.

Phosphorescence is generally a chemical relaxation of a material after its been irradiated and excited by UV-Vis light.

I think that you may be making an analogy for chemical excitation change and relaxation for gamma or x-rays. This is not like phosphorescence.

But, you can get high energy EM flourescence (an x-ray technique utilises this).

You can also get lots of known changes in materials intitiated by gamma and x-radiation.

You could also get fluorescent and phosphorescent materials in common products which contained radioactive materials (watch dials, instrument dials, glass ware etc). You'd need to go to an antique store nowadays to buy these.

In the past when fashion, excitement and quackery held sway without a knowledge of radiological effects you could even get your dentures considerably radioactive (enough to cause great concern nowadays).

Marie Curie was even awarded some presidential award medal which contained (approrpriately) a whole curie (37 GBq) of radium.

In the bizarre world of radiation and radioactivity (ie very common nature) at present your toilet, walls and floors, gardens and roads as well as your food, atmosphere are all detectably radioactive due to good old nature being herself.

Gamma-X irradiation of food and therapeutics is a reliable sterilisation or preservation method.

I doubt you'd like your med plastics microwaved or autoclaved!

Mouse Drip, Greenacres by the sea Oz
August 26, 2013 1:24am

"It's common in Europe, where refrigeration infrastructure has historically not been so great"
Say... what??? It doesn't seem to be so common in Europe since only 7 countries authorize it for something other than dried herbs and spices, and all in all the list of products actually submitted to this type of sterilization is very restrictive, and a total of 8000 tons of products irradiated in 2012, which is virtually nothing.
But really, my main question is: where did you get that strangest of notions about refrigeration infrastructure in Europe???

Bruno HANQUIER, Paris, France
May 17, 2014 8:22am

A reasonable documentary overview of the status of Food irradiation To June 2015 from a mob called The Institute of Food Science and Technology given that National standards can be quite expensive to obtain;

and for the people down here in Oz & NZ the blurb from FSANZ

Mulga Gill, Sydney
June 22, 2015 12:49am

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