Friday, July 30, 2010

Fact Sheet: Irradiation Using Electron Beams

What is electron-beam irradiation?

* E-beam irradiation uses an electron 'gun' to send high-speed electrons into a food. The electrons smash into molecules in the food as well as bacteria, damaging their DNA and creating free radicals and new chemicals. Nuclear irradiation uses nuclear materials that emit high-speed gamma rays, which have the same effect on food.
* E-beam irradiation is a fairly new technology, joining x-rays and gamma radiation. Until 2000, almost all food irradiated in the U.S. came from facilities using radioactive cobalt-60.

Other than the environmental risks, how does it differ from irradiation using nuclear materials?

* Because the electrons can be propelled at higher speeds, giving the beams more energy than gamma rays, e-beam irradiation can do more damage to the food than nuclear irradiation.
* E-beam irradiation is cheaper to use because the facilities do not require thick walls, containment pools or disposal of radioactive materials. Also, the food can travel through the irradiation facility much more quickly because e-beams have higher energy and penetrate more quickly than gamma rays.
* The choice of which irradiation method to use depends on several factors, especially the size and shape of the food to be irradiated. E-beams penetrate approximately one inch, so they are suited for evenly shaped, flat material like hamburger patties. For large, irregularly shaped foods (e.g., a whole turkey carcass) nuclear or x-ray irradiation is necessary.
* Unlike nuclear irradiation, e-beam irradiation may induce a trace amount of radioactivity in certain foods
* Both kinds of irradiation can injure workers exposed to the radiation.
* Both kinds of irradiation are offshoots of military technology. E-beam irradiation was developed for Star Wars. Nuclear irradiation began with "Atoms for Peace" in the 1950's. Its main advocate is the Department of Defense, which sees nuclear irradiation as 1) a commercial use for nuclear power plants (cobalt-60 has to be manufactured in a nuclear reactor), 2) a way of disposing of nuclear wastes and 3) a way to 'soften' the image of nuclear power.

Why we don't like e-beam irradiation

* For those irradiated foods that are labeled, the label does not reveal the source of the irradiation. Food regulatory agencies do not distinguish between nuclear and e-beam irradiation.
* If accepted by the public, e-beam irradiation will open the door for a re-introduction of nuclear irradiation. The U.S. Department of Energy is currently considering reopening a nuclear plant in Hanford, Washington, for food irradiation.
* Acceptance of e-beam irradiation by the public will support the food industry's efforts to remove all labels on irradiated foods. If labels are removed, the US will pressure countries that require labels to accept unlabeled US products. If other countries cannot enforce their labeling laws, irradiation will become much more common. And in most of the world, irradiation means only nuclear irradiation, because a reliable supply of cheap electricity does not exist. To summarize, e-beam irradiation in the US is the tip of the wedge that will lead to nuclear irradiation in most of the world.

Who is using electron-beam irradiation?

* In the US, the military-technology-transfer company Titan has built e-beam facilities in Iowa and Arkansas. They have signed agreements in Japan and Brazil to build e-beam facilities.
* US companies that have announced plans to use e-beam irradiation or buy e-beam irradiated products in 2000 include IBP, Excel, Tyson, Kraft, Wal-Mart, Emmpak, Huisken Meats, and smaller meat producers. (Kraft expects to use irradiation for its Oscar Mayer line, although the FDA has not yet approved irradiation for lunch meats.) Because IBP and Excel are two of the largest meat producers in the US, and the big contamination problem is ground beef, some of their e-beam meat is certainly going to fast-food restaurants for hamburgers.
* Because irradiated food that is sold to restaurants, schools and other institutions does not have to be labeled for the consumer, it is impossible to know how much irradiated beef and chicken is currently being sold to the public. The USDA approved irradiation for meat in February 2000, and some is already being used. Huisken, a Minnesota company, began shipping e-beam irradiated beef to retailers in Minnesota in May 2000.
* A Hawaii company is building an e-beam facility to irradiate papayas and small amounts of other tropical fruits, to open in July 2000.

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