Chemicals Formed During
Food Irradiaton Can Be Harmful

The U.S. Food and Drug Administration (FDA) has ignored growing evidence that a new class of chemicals formed when food is irradiated could be harmful, according to a report released today by Public Citizen and the Center for Food Safety.
The groups are urging the FDA to refrain from legalizing irradiation for any additional types of food until the new chemicals are tested for safety. The chemicals, called cyclobutanones, do not occur naturally anywhere on Earth. They recently were found to cause genetic damage in rats, and genetic and cellular damage in human and rat cells.
The groups' report, Hidden Harm, details how the FDA has ignored this unique class of chemicals, which are created in many irradiated foods that the agency has legalized for sale in this country -- including beef, pork, chicken, lamb, eggs, mangoes and papayas. It is expected that cyclobutanones also would be formed in many other foods the FDA is currently considering to legalize for irradiation.
The organizations today also released a sworn affidavit of toxicologist William Au, who was retained by the groups to independently review the risks posed by cyclobutanones and other chemicals formed by irradiation that could cause genetic damage.
Along with a letter outlining numerous health concerns caused by food irradiation, the groups filed Hidden Harm and Au's affidavit with the FDA to oppose pending petitions to legalize irradiation for processed foods, which comprise 37 percent of the typical American's diet; molluscan shellfish, such as clams and oysters; crustacean shellfish, such as lobsters and shrimp; and meat products.
A fifth petition seeks to double the maximum dose of radiation to which poultry can legally be exposed.
"The risk that the FDA is taking with the health of the American people cannot be overstated," said Wenonah Hauter, director of Public Citizen's Critical Mass Energy and Environment Program. "If government officials knowingly allow people to eat food that contains these chemicals, they are courting a major public health disaster."
Though federal regulations require the FDA to determine whether food additives proposed for human consumption are likely to cause cancer, birth defects or other health problems, the agency has not done so for cyclobutanones, nor have agency officials explained why they have failed to do so. Under federal law, irradiation is considered a food additive.
Americans likely are unwittingly eating irradiated foods containing cyclobutanones. Though most irradiated food sold in stores must be labeled, there is no such requirement for restaurants, schools, hospitals, nursing homes and other institutional settings. And there is no labeling requirement for foods with irradiated ingredients, except those containing irradiated meat. Moreover, due to a lack of reporting requirements for food companies, it is unknown how much irradiated food is sold in the US, or where.
"Children are likely to be especially vulnerable to the risks of these untested chemicals in their food," said Peter T. Jenkins, policy analyst at the Center for Food Safety. "It is beyond me why the FDA would take a chance by exposing American children in this way. The science is against it."
Au, an environmental toxicology professor at the University of Texas Medical Branch in Galveston, is internationally recognized for his work on the toxicological mechanisms that induce human disease. For more than 20 years he has taught, published peer-reviewed research and served on expert committees. He has received numerous awards, and has published or co-published more than 100 articles.
"An emphasis should be placed on the products that are unique to the irradiation process and that are potentially mutagenic, e.g. 2-DCB [2-dodecylcyclobutanone]," Dr. Au wrote in the affidavit. "Without conclusive evidence regarding the safety of these products, the safety of irradiated food cannot be assured." Au urged the FDA to "seriously and explicitly" consider "repeated observations" of genetic damage and reproductive toxicity in feeding experiments.
Though cyclobutanones were first identified in irradiated food in 1971, it was not until 1998 that German government scientists discovered that one type of cyclobutanone, 2-DCB, caused genetic damage in rats, and genetic and cellular damage in human and rat cells.
Subsequently, the scientists found that two other types of cyclobutanones -- 2-TCB and 2-TDCB -- caused genetic and cellular damage in human cells. Rat feeding studies of these two chemicals are expected to be completed soon.
Despite these findings, the FDA not only has failed to publicly acknowledge the potential risks posed by cyclobutanones, but the agency proceeded to legalize irradiation for three classes of food even after the first two German studies were made public.
Last year, the FDA legalized the irradiation of eggs, juice and sprouting seeds despite the fact that several high-ranking agency officials four months earlier had attended an international conference in Beijing at which the 2-DCB toxicity findings were presented and discussed.
Ironically, cyclobutanones are so easily detectable and have been known to remain in food for such lengthy periods - more than a decade - that they are commonly used as "markers" to determine whether food has been exposed to ionizing radiation.
The groups are calling on the FDA to take several steps: refrain from legalizing irradiation for any additional foods until comprehensive, published, peer-reviewed research is conducted on cyclobutanones; conduct a comprehensive analysis of the cyclobutanone levels in foods covered by irradiation petitions already approved by or pending before the FDA; convene public hearings to thoroughly explore the potential health effects of cyclobutanones.
Expert Affidavit on Safety of Irradiated Food
By William W. Au, Ph.D.
William Au, being duly sworn, hereby deposes and says:
A. My address is: Division of Environmental Toxicology, Department of Preventive Medicine and Community Health, Ewing Hall, 700 Harborside Drive, University of Texas Medical Branch, Galveston, Texas 77555-1110, where I have been employed as a Professor since 1991. My Curriculum Vitae is attached hereto indicating my professional qualifications as a toxicologist. My primary research interest is in conducting molecular and cellular studies to elucidate toxicological mechanisms for the induction of human disease. Since obtaining my Ph.D. from the University of Cincinnati, I have more than 20 years of experience teaching, conducting and publishing peer-reviewed research, consulting and speaking internationally, editing professional publications, and serving on numerous expert committees. I am a member of the major scientific societies related to toxicology and have received approximately one dozen awards recognizing my professional contributions. I have delivered more than 35 invited lectures internationally and published or co-published more than 100 articles in the toxicology field.
B. I submit this Affidavit on the food irradiation petitions pending before the United States Food and Drug Administration, most specifically FAP 9M4697 (Docket No. 99F-5522), addressing "ready-to-eat foods," however, the conclusions herein also apply generally to other past and pending irradiation petitions.
C. I submit this Affidavit on behalf of two Washington, DC, non-profit groups, the Center for Food Safety and Public Citizen, who have retained me as a consulting expert. Prior to this consultation I had no prior involvement with those or any other non-profit groups involved in food irradiation issues.
D. In formulating my opinion, I have reviewed relevant documents and studies that were provided by my clients and conducted independent research including several publications that I have selected from the literature.
My opinion, based on a reasonable degree of scientific certainty, is as follows: Ionizing radiation is a well-documented teratogen, mutagen and carcinogen whereas some other procedures for food decontamination / sterilization such as heat and steam are not. Ionizing radiation interacts with cellular macromolecules that are also present in food products to generate toxic products. Therefore, the use of radiation to decontaminate/sterilize foods that are destined for human consumption should be evaluated for health concerns very carefully. Whenever other processing methods or combination of methods that are equally effective in reducing the risk of food borne disease are available, the use of the radiation procedure should be avoided.
Therefore, it is surprising to learn from the Food and Agriculture Organization/International Atomic Energy Agency/World Health Organization report (1999) that those agencies gave a blanket statement of approval in the conclusion section "the study group concluded that no upper dose limit need be imposed." (p. 161). This decision can lead to misuse of the procedure in processing food for human consumption. Some reports in the peer-reviewed literature on mutagenic activities of irradiated foods were not considered in the 1999 FAO/IAEA/WHO report (Bhaskaram and Sadasivan, 1975; Vijayalaxmi, 1975, 1976, 1978; Vijayalaxmi and Sadasivan, 1975; Vijayalaxmi and Rao, 1976).
Although the observations from these studies are not confirmed by some publications in the literature, the positive findings have support from other publications (Bugyaki et al, 1968; Moutschen-Dahmen, et al., 1970; Anderson et al., 1980; Maier et al., 1993). Furthermore, repeated observations of activities that have significant public health implications such as polyploidy in somatic cells, genetic alterations in germ cells and reproductive toxicity should not be ignored, but should be considered seriously and explicitly by FDA with respect to the pending food irradiation petitions.
Radiolytic products are formed during the irradiation of food (Schubert, 1969). Their potential health hazards have not been adequately evaluated. An emphasis should be placed on the products that are unique to the irradiation process and that are potentially mutagenic, e.g. 2-dodecylcyclobutanone (Delincee and Pool-Zobel, 1998; Delincee et al., 1998). The quality and quantity of these radiolytic products may be different from one food type to another. Without conclusive evidence regarding the safety of these products, the safety of irradiated food cannot be assured. Conclusive evidence of safety of these products can be derived from in vivo studies published in peer-reviewed journals.
The formation of hazardous free radicals in irradiated food that can cause DNA damage is of serious concern. For food with high water content, the free radicals are rapidly degraded after irradiation. Therefore, human exposure to the free radicals through the food chain is minimal. For food with low water content, the Food and Drug Administration stated that "irradiated dry spices and seasonings are examples of foods in which free radicals are known to persist for long periods of time." (FDA, 1986, p. 13379).
However, the FDA concluded that this should not be of concern based on the manner in which these foods are used. On the other hand, the concerns for other dry foods that are consumed without further cooking and that are consumed in large quantities, such as dried fruits and nuts, are not considered. This possibility should be evaluated to determine the potential for exposing consumers to free radicals. This concern should be included in the FDA?s analysis of the "ready-to-eat food" irradiation petition, FAP 9M4697.

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