Text and Photos by Henrylito D. Tacio
Contrary to what most people may think, irradiated foods are safe to eat! This assurance came from Luvimina G. Lanuza, head of the Irradiation Services Section of the Philippine Nuclear Research Institute (PNRI), a line agency of the Department of Science and Technology (DOST).
“Irradiated foods are not radioactive and are therefore safe to eat,” said Lanuza during a techno forum held last year at SMX Convention Center. She explained that food items are subjected to gamma irradiation technology, whose energies used in irradiation don’t make the foods radioactive.
“Irradiated food has been exposed to radioactivity but does not become radioactive itself,” pointed out the Food Standards Agency (FSA) of the United Kingdom. Irradiating food is similar to that of pasteurization, cooking, or other forms of heat treatment.
The most common techniques of food irradiation, aside from gamma rays, are X-rays and electron beams.
Gamma radiation is used routinely to sterilize medical, dental, and household products. In addition, it is used for the radiation treatment of cancer. X-rays, produced by reflecting a high-energy stream of electrons off a target substance into food, are also widely used in medicine and industry to produce images of internal structures. Gamma rays and X-rays share some characteristics with microwaves, but with much higher energy and penetration.
Electron beam, which is similar to X-rays, is a stream of high-energy electrons propelled from an electron accelerator into food.
“Food absorbs energy when it is exposed to ionizing radiation,” the FSA said. “The amount of energy absorbed is called ‘absorbed dose,’ which is measured in units called grays (Gy) or kilograys (kGy), where 1kGy is equal to 1,000Gy. The energy absorbed by the food causes the formation of short-lived molecules known as free radicals, which kill bacteria that cause food poisoning.”
A joint expert committee on food irradiation concluded that “the irradiation of food up to an average close to 10 kGy causes no health hazards and guarantees no nutritional or microbial problems.”
Food poisoning is one of the main reasons why astronauts and cosmonauts generally bring irradiated foods when traveling to outer space. With so many things to worry about, the space travelers try to eliminate the fear of possible food poisoning from their list of problems.
Several studies show irradiation can effectively eliminate organisms that cause foodborne illness, such as Salmonella, Campylobacter, Listeria, and Escherichia coli.
In the United States, the Food and Drug Administration (FDA) has approved irradiation of meat (beef, pork, and lamb) and poultry (chicken) and allows its use for a variety of other foods, including fresh fruits and vegetables and spices. Some foods, such as dairy foods and eggs, cannot be irradiated because it causes changes in flavor or texture.
While irradiation cannot make food radioactive, it does reduce the nutrition and change the flavor, just like cooking. “Irradiation causes a multitude of chemical changes,” notes Wikipedia, the free encyclopedia. “A few of these products are unique but not considered dangerous. Cooking, smoking, salting and other less novel techniques cause the food to be altered so drastically that its original nature is almost unrecognizable.”
But irradiated foods are still nutritious. “All known methods of food processing — even storing food — can lower the content of some nutrients, such as vitamins,” says a brochure, Preserving Food and Agricultural Products by Radiation, published by DOST-PNRI. “At low doses of radiation, nutrient losses are not significant. Even at higher doses, irradiation does not adversely affect the nutritional quality of food.”
However, irradiation cannot be used to make spoiled food good or to clean up “dirty foods.” The brochure pointed this out: “Neither irradiation nor any other food treatment can reverse the spoilage process and make bad food good. If food already looks, taste or smells bad (signs of spoilage), it cannot be ‘saved.’”
The first definite work with radiation preservation was carried out on hamburgers at the Massachusetts Institute of Technology in 1943. It showed that high doses of X-rays could sterilize hamburgers.
Considerable scientific research over the past five decades indicates that food irradiation is a safe and effective form of processing. In fact, it has been approved in 50 countries, including Australia, the United States, Japan, China, France, and Holland.
At least three internationally recognized bodies support food irradiation: the World Health Organization (WHO), the American Dietetic Association, and the Scientific Committee of the European Union.
But despite this, food irradiation has not gained popularity among food consumers. Until now, people are incredibly reluctant to accept the irradiation process for the preservation of foods.
“The reluctance of consumers in some countries to accept irradiated food arises from the fact that anything associated with nuclear energy is considered by many people to involve danger and radioactivity,” said an article which appeared in World Health, a WHO publication.
The article said most consumer resistance to the irradiation process had been based more on emotional rather than technical factors. “The general public should come to terms with irradiation and accept it as another important method of food preservation,” it pinpointed.
Aside from food preservation, irradiation can also control pests. According to the UN Food and Agriculture Organization, about 25% of all food produced worldwide is lost after harvesting to insects, bacteria, and spoilage.
“Food irradiation can help reduce losses and can also reduce dependence on chemical pesticides, some of which are extremely harmful to the environment,” said a brochure prepared by the Food Irradiation Education Group of the University of Wisconsin (UW).
Irradiation can also be used to sterilize foods, “which can then be stored for years without refrigeration.” Sterilized foods are useful in hospitals for patients with severely impaired immune systems, such as patients with Acquired Immune Deficiency Syndrome or undergoing chemotherapy.
In Australia and New Zealand, only herbs and spices, herbal infusions, and some tropical fruits are approved for irradiation. In Europe, no foods other than dried aromatic herbs, spices, and vegetable seasonings are permitted for the application of irradiation.
In the Philippines, the Bureau of Food and Drugs has issued conditional clearance for the irradiation of onions, garlic (for sprout inhibition), and spices (for microbial decontamination).
“Food irradiation is still in the pilot stage in this country, but fruit irradiation for quarantine processing to export to the US is expected to take place in the near future,” said a news report.
Again, here’s Lanuza: “The irradiation of food is justified when it fulfils technological requirements and if it is beneficial for the protection of consumer health.”
Just a reminder: “Irradiation is not a replacement for proper food-handling. Irradiated foods need to be stored, handled and cooked in the same way as non-irradiated foods, because they could still become contaminated with disease-causing organisms after irradiation if the rules of basic food safety are not followed.”