Sworn affidavit of University of Texas toxicologist William Au raising concerns about the risks posed by chemicals formed in irr

In the Matter of Food Irradiation Petitions
Pending before the United States
Food and Drug Administration

October 28, 2001?

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.

  1. My opinion, based on a reasonable degree of scientific certainty, is as follows:
  1. 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.
  2. 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.
  3. 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.
  4. 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.

Dated this 10th day of October, 2001, at Houston, Texas.


State of Texas


County of Harris

Subscribed and sworn to before me this 10th day of October, 2001.

Josie Jones
Notary Public

State of Texas


(C.V. attached)


References Cited:

Anderson, D., Clapp, M.J.L., Hodge, M.C.E., Weight, T.M. Irradiated laboratory animal diets dominant lethal studies in the mouse. Mutat. Res. 80, 333-345, 1981.

Bhaskaram, C., Sadasivan, G. Effects of feeding irradiated wheat to malnourished children. Am. J. Clin. Nutri. 28:130-135,1975.

Bugyaki, L., Deschreider, A.R., Moutschen, J., Moutschen-Dahmen, M., Thijs, A., Lafontaine, A. Do irradiated foodstuffs have a radiomimetic effect? II. Trials with mice fed wheat meal irradiated at 5 Mrad. Atompraxis 14:112-118, 1968.

Delincee, H., Pool-Zobel, B.L. Genotoxic properties of 2-dodecylcyclobutanone, a compound formed on irradiation of food containing fat. Radiat. Phy. Chem. 52:39-42,1998.

Delincee, H., Pool-Zobel, B.L., Rechkemmer, G. Genotoxicity of 2-dodecylcyclobutanone. Food Irradiation: Fifth German Conference, Report EFE-R-99-01, Federal Nutrition Research Institute, Karlsruhe, Germany, 1998.

FAO/IAEA/WHO report. High dose irradiation: wholesomeness of food irradiated with doses above 10 kGy. World Health Organization, Geneva, 1999.

Food and Drug Administration. Final Rule, Irradiation in the Production, Processing, and Handling of Food, 51 Fed. Reg. 13376, Fri. Apr. 18, 1986.

Maier, P., Wenk-Siefer, I., Schawalder, H.P., Zehnder, H., Schlatters, J. Cell-cycle and ploidy analysis in bone marrow and liver cells of rats after long-term consumption of irradiated wheat. Fd. Chem. Toxic. 31:395-405, 1993.

Moutschen-Dahmen, M., Moutschen, J., Ehrenberg, L. Pre-implantation death of mouse eggs caused by irradiated food. Internat. J. Rad. Biol. 18: 201-216, 1970.

Schubert, J. Mutagenicity and cytotoxicity of irradiated foods and food components. Bull. Wld. Hlth. Org. 41:873-904,1969.

Vijayalaxmi. Cytogenetic studies in rats fed irradiated wheat. Int. J. Radiat. Biol. 7:283-285,1975.

Vijayalaxmi. Genetic effects of feeding irradiated wheat to mice. Canad. J. Genet. Cyto. 18:231-238,1976.

Vijayalaxmi. Cytogenetic studies in monkeys fed irradiated wheat. Toxicology 9:181-184,1978.

Vijayalaxmi and Sadasivan, G. Chromosome aberrations in rats fed irradiated wheat. Int. J. Radiat. Biol. 27:135-142,1975.

Vijayalaxmi and Rao, K.V. Dominant lethal mutations in rats fed on irradiated wheat. Int. J. Radiat. Biol. 29:93-98,1976.