Those of us living in the developed world have come to expect our food to be clean and safe. That’s why outbreaks of foodborne illness can elicit a sort of primal fear, especially when seemingly wholesome foods like salads are involved. In spite of the efforts of growers, distributors, the government, and the public, the CDC estimates that 48 million Americans get sick every year as a result of foodborne illness, with 128,000 requiring hospitalization and 3,000 dying.
How can food be made safer? One answer is irradiation. This may not be the answer you want to hear. There’s still opposition to food irradiation, and several organizations (such as Public Citizen and Food & Water Watch) continue to campaign against it. They claim it’s not the solution to food safety problems and may actually be harmful.
But there’s also a long list of supporters, including the USDA, FDA, EPA, CDC, World Health Organization (WHO), and American Public Health Association. About 60 countries allow food irradiation. NASA gives astronauts irradiated food when they are on a mission to prevent foodborne illness, which would be especially bad news inside a space capsule.
Let’s sort out the facts and myths about irradiation.
What is food irradiation?
It’s a process by which food is exposed to radiation in order to kill harmful bacteria and parasites and sometimes deactivate viruses; control infestation by insects (such as fruit flies that may hitchhike on imported produce); delay ripening and prevent sprouting of produce; and prevent or delay the growth of molds and bacteria that cause food spoilage. When higher levels of radiation are used, the process can sterilize foods so they can be stored without refrigeration for years, be served in hospitals to immune-compromised patients, or be sent on space missions.
Irradiation has become an important way to ensure that foods marketed internationally meet quality and safety standards, especially since some countries limit or prohibit many chemicals used to protectfoods. There is also increasing appeal for the technology to help reduce the enormous amount of food waste that occurs worldwide due to contamination and spoilage. According to a food irradiation industry trade group, more foods are being irradiated than ever before in order to be sold in the global market.
Three technologies are used:
- Electron beams (e-beams) from an electron gun, the kind of apparatus in the back of the picture tubes found in old TVs, which propelled electrons onto the screen. E-beams are used by manufacturers for sterilizing some medical equipment. This is the most common method of food irradiation.
- Radiation (gamma rays) from radioactive cobalt 60 or cesium 137—a method that’s also used to sterilize medical equipment and to treat cancer.
- X-rays, similar to those used in medicine.
Food irradiation can be likened to pasteurization, a heat-treatment process that kills pathogens in milk and other liquids—except that the ionizing radiation used in food irradiation does not produce heat, which is why the process is sometimes referred to as “cold pasteurization.”
Are irradiated foods unsafe in any way? Do they taste different? Are their nutrients reduced?
According to the FDA, there is no evidence of safety issues associated with the irradiation of food. In addition, based on decades of research, the WHO, the United Nations’ Food and Agriculture Organization (FAO), and the International Atomic Energy Agency jointly agreed that irradiated foods are safe and wholesome. Opposition groups counter that food irradiation creates “radiolytic byproducts” (including mutagens and volatile toxic compounds), while proponents say these are not of toxicological significance.
While any processing (cooking, for example) changes food to some extent, irradiation doesn’t significantly change the appearance, taste, or texture of food. Opposition groups, however, maintain that the process can create unappetizing off-flavors.
Any vitamin losses from irradiation are insignificant and considerably less than those caused by heating or canning. Minerals are not affected by irradiation.
In fact, by helping to prevent the spoilage of fruits and vegetables, irradiation slows the natural loss of vitamins over time. Still, it does not halt aging of foods and the eventual loss of nutritional value over the longer term.
Which foods are approved for irradiation in the U.S.?
The FDA has approved pork, beef, poultry, fresh fruits and vegetables, spinach and lettuce, eggs in the shell, shellfish, sprouting seeds, and spices and seasonings. Many imported foods are irradiated in the countries where they are produced, before they are shipped. Recently added to the list are lychees and mangoes from Australia, figs and pomegranates from Peru, and starfruit and mangoes from Vietnam. Canada now allows ground beef to be irradiated, something that its beef industry had wanted since the late 1990s.
But just because a food has been approved for irradiation does not mean you will find it in most stores. In fact, marketing of irradiated foods is still limited, probably because of consumer resistance.
Are irradiated foods labeled?
The international symbol that must be shown on irradiated foods is referred to as the “radura,” a stylized plant in a circle. In the U.S. and Canada, irradiated foods sold retail must also be labeled “treated with radiation” or “treated by irradiation.” Bulk foods, such as fruits and vegetables, are required to be individually labeled or to have a label posted nearby. However, labeling is optional on processed or packaged foods that contain an irradiated ingredient (such as a spice). Labeling is not required on food served by restaurants, schools, or catering establishments.
If you buy irradiated foods, is it less important to wash and refrigerate them? Can you throw out your meat thermometer?
No and no. Opponents of food irradiation often claim that government and industry will use it merely as a substitute for safe food practices, but regulations do not permit this. Food should be clean and is usually in a package before it’s irradiated. But it is possible for contamination to occur after irradiation.
Irradiating food is no substitute for proper preparation, cooking, and storage at home. Irradiation doesn’t eliminate toxins that may have been in the food, such as the toxin produced by the bacteria that cause botulism. You still need to wash produce and refrigerate irradiated foods. Meats still need to be fully cooked.
How dangerous are the processing plants? Do they pollute the air or water?
As in hospitals and other medical facilities, people working around irradiation machines must be shielded from the rays and must follow safety protocols. Food irradiation facilities are regulated by the government and are subject to regular inspections and reviews to ensure safety.
Whether intended for medical or industrial use, cobalt 60 and cesium 137 are made in nuclear reactors. When such radioisotopes are shipped, there are stringent regulations to ensure safe transport. Medical facilities in the U.S. have used these substances for decades without any fatal accidents. Unlike the rods from nuclear power plants, they are not regarded as “problematic waste.”
There have been a few incidents of leakage and contamination, but neither people nor the environment have ever been exposed in this country. The plants do not produce air or water pollution. And no radioactive gases are released. E-beam and X-ray facilities produce no radioactive substances and no waste. Radiation stops when the machines are turned off.
What are the downsides?
Some of the concerns about irradiated foods are emotional or philosophical. The “radiation” part of irradiation scares some people, even though irradiated foods are not radioactive. In an era when many people yearn for unprocessed or less-processed foods, consumers may resist the idea of one more form of processing.
Another potential problem: Since food is usually packaged before being irradiated, there is the concern that compounds in the packaging may be released and migrate into the food. The FDA regulates all packaging materials used in food irradiation, but scientists should continue to monitor this.
If you want to avoid buying irradiated food, is that possible?
Yes. Out of the tens of thousands of food items available in supermarkets, only a very small percentage are typically irradiated, including some papayas and other imported fruit, some ground beef, and spices. But one sure way to avoid it is to buy USDA certified organic foods, which cannot be irradiated under the organic standards—though they typically cost more.
Bottom line: Widespread food irradiation could greatly reduce the risk of foodborne illness and improve the shelf life of food. It could be a real asset in developing countries where food is limited and refrigeration is scarce, provided workers are protected and proper safeguards are observed. Still, it cannot be overemphasized that irradiation is no magic bullet. It can never substitute for cleanliness and safety precautions by food producers as well as by consumers.