Food Irradiation

Diba Massihpour
March 20, 2017

Submitted as coursework for PH241, Stanford University, Winter 2017


Within the food industry, many producers have found roadblocks in terms of food preservation. Causes of food spoiling include infestation, contamination, and deterioration. Many regions in warmer climates, especially those in developing countries with access to little resources and technology, have difficulty keeping foods that require to be chilled cold, leading to their spoiling. Aside from contributing to an overall loss in food storage, the spoiling of food can lead to a number of health complications. According to a 1983 study done by the Joint FAO/WHO Expert Committee on Food Safety, it was discovered that one of the largest health concerns was disease related to foodborne illnesses. [1] Many other food preservation methods exist, including "salting, cooking, smoking, canning, freezing, and chemical preservation." [1] However, irradiation is the most controversial of these methods due to the misconceptions surrounding the process and its benefits and harm.


The process of food irradiation can be done in two ways, one involving the use of accelerated electrons and the other gamma rays/X-rays. Using accelerated electrons requires an electron gun which shoots out a stream of high energy electrons. The electrons penetrate approximately 1.5 centimeters into the food, so the food must be thinner in order to be fully treated. [2]

Food irradiation by X-ray similarly uses a stream of electrons but directs them at a metal plate to produce X-rays. The metal plates are produced of materials such as tungsten, steel, or tantalum. The X-rays can penetrate a thicker depth of food than accelerated electrons, over 24 inches. The downside of using X-rays for food irradiation is that the costs of doing so are very high. [2]

Similar to irradiation by X-ray, gamma rays use radioactive substances with specific energies to emit rays that are then absorbed by the food. Gamma irradiators can penetrate more than 24 inches into food if irradiated on both sides. The downside of gamma ray irradiation is that only certain radioactive substances can be used for the process: for example, Cobalt-60 is a common source. [2]

Health Benefits vs. Misconceptions

Irradiation can specifically target the prevention of foodborne diseases, insect control with regards to food, sprouting and ripening delay, sterilization, and preservation. Moreover, food irradiation does not change the nutritional content of the food, so all the benefits of consuming the food remain even through the radiation. [3] Amino acids and other nutrients in food are not lost or diminished in nutritional value through the process of food irradiation. [4] In other words, there is no harm to the quality of the food itself when it undergoes irradiation.

According to the FDA, the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture (USDA), irradiated food is safe for consumption. [5] In fact, the National Aeronautics and Space Administration (NASA) requires that their astronauts only consume irradiated food in order to protect their health when they are in space. [3]

Downsides of Food Irradiation

Contrary to some misconceptions, food irradiation does not make food radioactive. However, food irradiation also does not entirely eliminate germs and diseases in food; it only reduces them. Moreover, food irradiation does not remove toxins produced by bacteria before the irradiation occurred or stop fruits and vegetables from the aging that lowers nutritional value and flavors. One downside of food irradiation is that it destroys the bacteria that is responsible for making the smell that indicates that the food is rotting. [3]


Food irradiation is an effective way to preserve the overall value of food, without causing any known health concerns, as the food does not become radioactive. Further research can be done to investigate how the process of irradiation can be used with other things for benefitted results.

© Diba Massihpour. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] Food Irradiation: A Technique For Preserving And Improving The Safety Of Food (World Health Organization, 1988).

[2] Food Irradiation Questions and Answers," Food Irradiation Processing Alliance, September 2006.

[3] "Food Irradiation," U.S. Environmental Protection Agency, EPA 402-F-06-046, April 2006.

[4] A. Eller, "The Validity of Certain Myths About Food Irradiation, Physics 241, Stanford University, Winter 2014.

[5] "Food Irradiation: What You Need to Know," U.S. Food and Drug Administration, June 2016.