Do you know what the international (smiley face) “RADURA” symbol means?

It is used to show a food has been treated with ionizing radiation: gamma rays produced by radioactive cobalt.  The word RADURA is derived from radurization, an artificial word combining the letters of “radiation” with the stem of “durus”, the Latin word for hard, lasting, or strong. 

The symbol was developed and copyrighted in the Netherlands during the 1960s, when an institute sponsored by the United Nations, at the invitation of the Dutch Government, undertook studies on food irradiation.  The icon was intended to denote food (as an agricultural product) represented by a plant (the dot and two leaves) in a closed package (the circle) irradiated from top through the package by penetrating gamma (ionizing) rays (the breaks in the upper part of the circle).  It was licensed to anyone who adhered to carefully delineated standards.

The intent was to make irradiated produce recognizable: the Radura logo was to indicate quality and purity, not a warning.  In Dutch supermarkets the logo was prominently displayed as a marketing tool to promote products of high quality coupled with extended shelf life.

Opponents to food irradiation feel the RADURA logo is deceptively “positive”: particularly, in its green color, illusion to “earth” imagery; perhaps even in its allusion to American “recycling” images. 

The US Federal Environmental Protection Agency (EPA) identifies itself with a similar two-leafed flower, with abstract waves symbolizing water and a half-circle suggesting a rising sun…
an untainted world. 

These associations, however, are appreciated by the US Food and Drug Administration (FDA): the agency’s Dr. Ronald Engel remarking “It was meant to be kind of like a smiley face, so people would recognize irradiated food and want it.” 

Alpha particles
Beta Particles
Gamma Rays

Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays.  These types of radiation are invisible to the naked eye (but can interact with nearby phosphorescent or florescent materials that will glow green: that’s why a green glow is associated with radioactivity).

Alpha particles are the nuclei of helium atoms: slow moving, they cannot penetrate the skin, but can cause severe damage if swallowed.  Beta particles are high-energy electrons that can penetrate through paper and even partially into the human body, but cause less damage than alpha particles.  Gamma rays are extremely high energy electromagnetic waves that can only be stopped with thick lead or concrete.

Within the meaning of the Atomic Energy Act of 1946 —(The McMahon Act) which determined how the United States would control and manage the nuclear technology it had jointly developed with its World War II allies, the United Kingdom and Canada—radioactive substances are: nuclear fuels, i.e.

1. plutonium 239 and plutonium 241;

2. uranium enriched with the isotopes 235 or 233;

3. any substance containing such components; or

4. substances which can be used in a suitable plant to maintain a chain reaction which initiates its own repetition and which are determined in an ordinance having the force of law;

5. also: other radioactive substances which, without being nuclear fuel, spontaneously emit ionizing rays, or contain or are contaminated with one or several of the substances mentioned.

What is a “URP”?

Food Safety Advocates disparage that other existing practices currently being used can accomplish similar goals.  For example, food-borne pathogens and insect infestations could be reduced by more sanitary and stronger regulated agricultural practices.  However, ionizing radiation produces better metrics and is more cost effective.

DNA makes
RNA makes Proteins

The three major biological macromolecules that are essential for all known forms of life are DNA (deoxyribonucleic acid: the hereditary material in humans and almost all other organisms), RNA (ribonucleic acid) and proteins.  A central tenant of molecular biology states that the flow of genetic information in a cell is from DNA through RNA to proteins; or: “DNA makes RNA makes protein.”

Food molecules are made up of atoms that ordinarily have no net electrical charge: each atom has a nucleus containing uncharged neutrons, and protons, which are positively charged; negatively charged electrons orbit around the nucleus.  But as the energetic particles or waves pass through the target material during irradiation, they collide with atomic particles, knocking them out of orbit. 

This is how irradiation kills bacteria: chemical bonds nearing the sites of these collisions are broken (radiolysis) that are vital for cell growth and integrity.  As a result, the microbes die, or can no longer multiply.  When the bonds are destroyed, it creates short-lived radicals (Hydroxyl radicals, hydrogen atom and solvated electrons).

As the biological cell loses its electrical balance, these radicals cause cascading chemical changes by ricocheting and bonding with and or striping particles from nearby molecules: creating unique radiolytic products and increasing the number of free radicals in the food.  When collisions damage DNA or RNA, effective reproduction becomes unlikely; also, when collisions occur in cells, normal cell division is suppressed.  Free radicals may combine with other chemicals to create a mix of known toxins (benzene, formaldehyde and lipid peroxides) and unique radiolytic products that
only exist in irradiated foods.

The radiation absorbed dose (RAD) is the amount of energy absorbed per unit weight of the target material.  Dose is used because, when the same substance is given an equal dose, comparable changes are observed in the target material.  The SI unit (the international system of units: The National Institute of Standards and Technology) for dose is grays (Gy or J/kg).  Dosimeters are used to measure dose, and are small components that, when exposed to ionizing radiation, change measurable physical attributes to a degree that can be seen and correlated to the dose received.  So, measuring dose involves exposing one or more dosimeters embedded in the pallet along with the target (dog food ingredient) materials.

Modern dosimeters are made of a range of materials, including alanine pellets, perspex (PMMA) blocks, and radiochromic films, as well as special solutions identified through specialized read-out devices and careful reporting/documentation proscribed by the American Society for Testing and Materials (ASTM international).  Doses are generally divided into low (up to 1 kiloGy), medium (1 kGy to 10 kGy), and high dose applications (above 10 kGy).  High dose applications are above those currently permitted in the USA for commercial food items by the FDA and other regulators globally.

Penetration of radiation types

Cherenkov radiation

The blue glow of the reactor pool is known as Cherenkov radiation, electromagnetic radiation understandable as similar to a “sonic boom,” such as a fighter jet causing an explosive form of feedback at it catches the rippling sound waves given off by its own engines.  A nuclear reactor can catch and interfere with light: radiation from nuclear material causes magnetic distortions in the water, super-charging water molecules until they release excess energy (throw out photons) which is amplified to a visible level as blue light.

Irradiation by X-ray is similar to irradiation by gamma rays in that less energetic packets of light (X-rays) are used.  In a process known as bremsstrahlung-conversion, X-rays are generated by colliding accelerated electrons with a dense material; and so do not necessitate the use of radioactive materials.  X-rays produce superior dose uniformity than Gamma irradiation with a similar ability to penetrate the target.  They are costly to produce, however, since only as much as 12% of the input energy is converted into X-rays.  X-ray facilities rely on extensive concrete shields to protect workers and the environment from radiation exposure.

Cost vs. Benefit Analysis of Irradiation

Establishing an irradiation facility is a capital-intensive endeavor ranging from $1 to $5 million.  A large research or contract irradiation facility would involve a radiation source, hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), substantial land, a radiation shield (perhaps a 20-foot thick concrete wall), and warehouse.  Fixed and variable operating costs are considerable including a specialized workforce, utilities, maintenance, insurance, cobalt-60 replenishment, disposal of radioactive waste, and a range of general operating costs.  The cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions (example: packaging and stacking requirements), financing arrangements, and other variables particular to the situation.

Global trade in irradiated food is limited, excepting minor quantities of fruit and ground meat products irradiated to eliminate insect pests and to fulfill US quarantine requirements.  Currently, Mexico is the largest exporter of irradiated produce to the US.  Analytical methods are available to conduct market surveillance to detect the usage of irradiation on food items, taken as a device for government authorities to enforce existing labeling standards and to encourage consumer confidence.  However, little information is available in readily understandable formats for consumer use in the marketplace.

The European Union has strict labeling requirements that many regard as restrictive, and as a result, it seems rare to find irradiated and clearly labeled food items on sale in
Community countries.

Irradiated food
poisons
cats

In 2009, however, Australia ended its government-mandated practice of irradiating imported pet food, following compelling evidence that cats can suffer fatal neurological damage after eating irradiated dry food.  About 90 cats fell ill (tetraplegia: paralysis of all four limbs and the torso) and 40 died before a Sydney vet, Georgina Child, connected the mysterious illness to the Canadian pet food Orijen.  The brand’s Canadian “co-packer” (contract manufacturer), Champion Petfoods (ED, AL), blamed the contaminated food on Australian quarantine regulations: which stipulated that pet food not cooked over a specified temperature undergo irradiation of 50 kiloGrays upon arrival in the country.  Champion stressed that of 60 countries they exported to, only Australia made irradiation compulsory.

The company stated:“When irradiation is applied to food, the molecular structure of long chain fatty acids (DHA, EPA) is altered. This causes the formation of free radicals that are then released into the body. ORIJEN CAT foods contain very high levels of EPA and DHA unsaturated fatty acids and therefore have a much greater potential for free radical formation (in response to irradiation) than do conventional dry cat foods.”

Both the Australian Quarantine and Inspection Service and Steritech (Charlotte, NC: the irradiation vendor), insisted that the process was harmless.  The limited feline necropsies that were performed were inconclusive—though critics stress that no one knew what to look for—and the Australian Veterinary Journal still maintains today that there is no known mechanism by which changes induced in foods by irradiation could stimulate the extent of injury.  Microscopic damage to the white matter of spinal cord and brain was seen; however, the issues have not been further explored.  Food Safety Advocates and other scientists suggest that  the answer was likely vitamin A deficiency: since irradiation destroys vitamin A.  This would confirm why only cats became sick on the food: dogs have the ability to synthesize their own vitamin A, but cats, as obligate carnivores, cannot.

Consumer advocacy groups[5]  and public health experts have expressed concern that irradiation endangers public welfare since it might be used to sanitize contaminated food (“counterfeit freshness”): therefore masking spoiled contents and making foods appear fresh longer.  In the case of pet foods, where FDA compliance policies specifically permit the use of such ingredients that would otherwise be prohibited by existing federal law—including that characterized as “contaminated,” “filth,” “contaminated with rodent, roach or bird excreta,” or “from already dead or diseased animals,” for example—this should be seen as a legitimate and paramount alarm.

Although the process of spoilage would be stopped, irradiation would not destroy the toxins already present: if the food contains botulism (not killable by irradiation) or other spoilage that would otherwise be noticeable by smell, irradiation would have eliminated the odor.  Further, radiation kills "beneficial bacteria" (probiotics) that inhibit the growth of pathogenic (disease causing) bacteria, and may also engender creation of radiation tolerant bacteria . 

It is feared that the ability to mask spoiled ingredients and finished foods—despite current regulations imposed on the irradiation facilities—could encourage even more lax safeguards in food processing facilities, and therefore lead to a greater introduction of contaminates: food producers could economize on sanitation, because they would have a “kill step” at the end of their food production process shortly before shipping.

The argument about the lack of long-term studies, and therefore, that the safety of irradiated food is not scientifically proven—despite that hundreds of animal feeding studies of irradiated food, including multigenerational studies, have been performed since 1950—is worth consideration.  Critics argue that the FDA has summarily dismissed hundreds of studies demonstrating adverse physical or microbiological consequences, instead relying on “obscure journals,” the US Army’s own food irradiation program, and industry-funded research.  Irradiated food is not radioactive, critics argue, but it is radiomimetic, or radiation imitating: the consumer (or pet) receives an indirect exposure to between thousands and millions of rads (a deprecated unit of absorbed radiation dose), by consuming the food.

Moreover, a toxic synergy occurs when multiple mycotoxins are present in a pet food or treat, amplifying the toxicological potentiation.[12]   Despite (false) assurances that pet foods are highly regulated, there is no regulatory maximum or cumulative level for pet food or animal feed for many mycotoxins, nor an established LOAEL (lowest observed adverse effect level) or no established NOAEL (no observable adverse effect level) for any mycotoxin in pet food or animal feed.

Additionally concerning is the problem of nutrients that are destroyed by irradiation.  At radiation levels currently used, vitamins A, C, E, and K, and the entire B group, are damaged by the process.  Amino acids and polyunsaturated fatty acids are also affected.  Proponents of food irradiation point out that all food processing methods entail the loss of some nutritional value… but irradiated foods will also undergo these other forms of food processing, further reducing their already depleted nutritional stores.  Because irradiation breaks down cell walls, accelerated vitamin losses occur during storage–up to 80%.  Ironically, irradiation both creates harmful free radicals and destroys the antioxidants necessary
to fight them.

irradiation both creates harmful free radicals
and
destroys the antioxidants necessary
to fight them.

The regulatory framework enfolding food irradiation attempts to integrate concerns about efficacy; plus chemical and microbiological safety.  The Codex Alimentarius represents the globally recognized standard for irradiation of food, organized under the World Trade Organization (WTO) agreement. 

At their discretion, member states convert those standards into national regulations, leading to some international variation.  The United Nations Food and Agricultural Organization (FAO) has committed member states to implement irradiation technology for their national phytosanitary programs (measures for the control of plant diseases, particularly in agricultural crops); and the General assembly of the International Atomic Energy Agency (IAEA) has urged wider use of irradiation technology.

According to the Codex Alimentarius, any “first generation” product must be labeled “irradiated,” as does any product derived directly from an irradiated raw material.  For ingredients, the provision is that even the last fragment of an irradiated ingredient must be listed with the ingredients, even in cases where an un-irradiated ingredient does not appear on the label.  The RADURA logo is optional (and several countries use a graphical version that differs from the Codex-version).  In this instance, the Radura symbol would not be a designator of “quality”: the sum of pathogens remaining is based upon irradiation dose and the original content.

In 2003, the Codex Alimentarius removed any upper dose limit for food irradiation as well as clearances for specific foods, declaring that all are safe to irradiate.

Pakistan and Brazil have adopted the Codex without any reservation or restriction: other countries, including New Zealand, Australia, Thailand, India, and Mexico, have permitted the irradiation of fresh fruits for fruit fly quarantine purposes,
amongst others.

The European Union (EU) follows the Codex's provision to label irradiated ingredients down to the last particle of irradiated goods.  Presently no foods other than dried aromatic herbs, spices and vegetable seasonings are permitted for the application
of irradiation. 

The EU does not provide for the use of the Radura logo and relies exclusively on labeling by the appropriate phrases in language of the respective member states.  Enforcement enfolds requirement that member states test a cross section of food items in the market-place and to report/publish annually in The Official Journal of the European Communities.  Owing to the "single market" concept of the EC: any food (even if irradiated) must be allowed to be marketed in any other member state even if a general ban of food irradiation prevails, under the condition that the food has been irradiated legally in
the state of origin.

Food Safety Advocates are sharply critical that the FDA’s Bureau of Foods Irradiated Food Committee (BFIC) supported this abrupt change (including blanket approvals) on review of only 5 of 441 available scientific studies, including one entitled: “On the Wholesomeness of High Concentrations of Free Radicals in Irradiated Foods.”  The FDA also made its assumptions pursuant to unilaterally declaring that then-current toxicity tests were not sensitive enough to determine the potential toxicity of Unique Radiolytic Products (URPs, see: discussion above).  And to date, no research has been conducted to analyze the potential for URPs to become stored in fatty tissues and accumulate, crossing the threshold (one part per million) set by the FDA.

FDA defends blanket dismissal of opposing research, including its denial of petitions for hearings to examine the agency’s decision on methodological and statistical grounds.

Shortly after, the FDA defended its blanket dismissal of opposing research, including its denial of petitions for hearings to examine the agency’s decision on methodological and statistical grounds.  Already approved for use in feeds for laboratory animals, the FDA permitted the use of irradiation for all pet foods in April 2001.

In the US each new food is approved separately with a guideline specifying a maximum dosage; in case of quarantine applications the minimum dose is regulated.  As a food “additive,” irradiated products are regulated by the FDA, but the US Department of Agriculture (USDA) amends these rules for use with meat, poultry, and fresh fruit.  The USDA has approved irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to insect pests, including fruit flies and seed weevils (such as those that breed in silos of grains used in pet foods).  Agreements are made with less developed countries to allow them to earn income through food exports agreements while allowing them to irradiate fruits and vegetables at low doses to kill insects, so that the food can avoid quarantine.

To support its public relations efforts, global agribusiness has engaged the American Council on Science and Health (ACSH), an industry lobbyist science education organization.  Defining itself as a scientific consumer education organization, the group operates under multiple slogans, including:  “First in science, first in influence,” and “We know the difference between a health hazard and a health hoax.”  The Center for Science in the Public Interest published an exposé in 1982 of the council that indicated the direction of its authority: “The ACSH receives most of its funding not from membership dues or foundation grants, but from private industry; specifically, from chemical manufacturers and a variety of food companies, (trade associations) and (chemical manufacturers)….”

In 2012, the FDA approved a petition from Sadex Corp. (St. Sioux City, IA) allowing irradiation of animal feed and pet food ingredients.  As discussed above, characterized as an “additive,” such products will not be required to bear identification (or the Radura symbol) for consumer disclosure.   Since 2007, Chinese-manufactured chicken, sweet potato, and duck jerky treats are believed causal in thousands of pet illnesses and deaths in the U.S and in Australia (they were recalled in Australia); but not in Europe.  Food Safety Advocates note that besides the country of origin (China), the common connection with the treats may be irradiation.

Sadex Corp. will be constrained by current US EPA regulations: foods for human consumption are limited to 1 kiloGray (kGy) for fresh foods and 3 kGy for fresh shell eggs (to eliminate Salmonella) and poultry. Frozen, uncooked meats have a higher limit, which is 7 kGy.  Pet food and treats can be treated with comparatively higher levels: up to a
maximum of 50 kGy.

Endnotes