Making food safer and longer-lasting | The Daily Star
12:00 AM, May 17, 2013 / LAST MODIFIED: 12:40 AM, May 17, 2013

Making food safer and longer-lasting

INTERNATIONAL food producers are struggling to find sustainable ways to grow food for the growing world population. This poses great challenges as the arable lands needed for cultivation are disappearing at an alarming rate while man-made expansion onto agro-based territories are putting strains on agriculture, causing food shortages or higher food prices in most countries.

Irradiation of food could directly address this challenge as its combined efforts, with best practices, proper sanitation and disease prevention hold great promise in providing adequate protection to the world's food supply. It can thereby reduce food-borne diseases, ultimately enhancing global health.

'Nuclear Food' Irradiation is the method of eliminating disease-causing germs by using specific radiation doses for a predefined period of time. It effectively slows spoilage due to pathogen growth since the radiation damages the target organism's DNA beyond its ability to repair. At higher dose levels, the organisms are destroyed altogether.

There are no nutritional losses in food as a result and it is safe and free of radioactive elements or traces. It is, however, still debated whether free radicals can increase risk of cancer or whether remaining 'radiation resistant' organisms may create extended strains or whether radiolytic products may form from residue. Moreover, it influences sanitation bad practices among farmers while the resulting longer shelf lives only provide more benefits to producers and the not primary consumers.

Sometimes called 'irradiation pasteurisation' or 'ionising radiation,' it is similar to conventional pasteurisation of food which kills microbes by producing strong energy waves that dislodge electrons from molecules and atoms. The resultant electrically charged particles or ions target organisms and kill or reduce microbes in food by 90% to 99.99%.

This can be done in three main irradiation processes. An electron beam generator is often used. It generates e-beam from electron guns or beam linear accelerators, where only a few inches of radioactive penetration occurs in food. The beam generator can be switched on or off and there are no radioactivity issues.

Next, Gamma Irradiation can also be utilised as photon radiation is obtained through radio isotopes Cobalt-60 or Cesium 137. Cobalt-60, which is bred from Cobalt-59, poses the least environmental risk and decays to non-radioactive nickel. It needs frequent replenishment with a half-life of 5.3 years. Cesium-137, on the other hand, is commercially unavailable for large scale irradiation. Finally, X-rays accelerators are also used as an alternative to isotope based radiation systems. Like Gamma rays, photon radiation through beam accelerator is highly penetrative and hence considerable shielding is required.

Irradiation can kill pests infesting food grains without leaving pesticide or chemical residue and can delay ripening so that food can be stored longer. In addition, the process can provide sterilised food for patients with compromised immune system.

Many government agencies have deemed irradiation safe because there is no environmental impact as radioactive materials are disposed of responsibly. Nuclear facilities involved with irradiation have a good safety and regulatory record, although they can potentially lead to statistically higher accident risks.

However, only a limited number of foods may be treated by radiation, and even that cannot eradicate all pathogens. It cannot kill seafood microbes like Norwalk virus. Certain types of food are commonly irradiated, like fresh and frozen meat, poultry and seafood. Vegetables, herbs and spices are also common in both fresh and frozen states, so are grains such as wheat and flour. Fruit also makes up a sizable portion among the world's irradiated foods. Cattle feed, fodder and other animal food such as those for pets are also increasingly becoming popular. The items are irradiated for various reasons, including control of microbial organisms, extending shelf life, delaying ripening of fruits and vegetables, reduced change in physical appearance, disinfestation of pests and insects, etc.

Irradiation regulations differ among countries around the world. In Bangladesh, the Institute of Food and Radiation Biology (IFRB) was established in 1979 for the peaceful application of nuclear energy in the field of biological sciences. The core facility of the Institute is a Cobalt-60 gamma irradiator and is operated and maintained by Gamma Source Division. Most research activities of the institute are based on gamma irradiation.

In addition to research, this source renders limited scale commercial service to private stakeholders, particularly to pharmaceutical industries. In New Zealand, Australia, Thailand, India, and Mexico, regulating agencies have permitted the irradiation of fresh fruit for fruit fly quarantine purposes, amongst others.

Food and Agricultural Organization (FAO) passed a motion to commit member states to implement irradiation technology. The General Assembly of the International Atomic Energy Agency (IAEA) has similarly urged wider use of irradiation technology. Furthermore, food irradiation has received official endorsement from global agencies such as World Health Organization (WHO).

Provisions in most regulations include mandates that any irradiated product must be labeled “irradiated“ for consumer awareness. In Europe, the centralised government—European Union (EU) -- regulates food irradiation and all member states abide by the EU directives. Because of the “Single Market” structure, any irradiated food must be allowed to be marketed in any member state.

In the United States, irradiation practices are primarily regulated by the Food and Drug Administration (FDA) while other federal agencies are also involved. For instance, the Nuclear Regulatory Commission (NRC) is charged with the safety of the processing facility, the US Department of Agriculture (USDA) deals primarily with meat, poultry products and fresh fruit, while the US Department of Transportation (DOT) is concerned with the safe transport of the radioactive sources and materials, and the US Department of Labor (DOL) and the Occupational Safety and Health Administration regulate the safety of workers in nuclear facilities.

Beyond international politics and regulations, food markets also create challenges as retail stores are unwilling to carry irradiated food mostly due to misunderstandings about radiation among consumers and the perception that it will keep them from buying and using the irradiated products. Agencies often claim that the public is unaware, and studies have shown that awareness is indeed key to acceptance.

Besides the issue of consumer opinion, there is an economic deciding factor as additional costs are incurred by consumers. There are not a lot of investments in irradiation because capital costs for radiation systems range from $4.4 million to $17 million. Proponents contend that costs would be offset in the form of decrease in food-borne illness and corresponding legal and punitive claims for spoilt products.

Food security is and will continue to be a major international issue, especially because there are expected to be around 9 billion people by 2050. Policy makers and scientists are continuously working to evaluate irradiation methodologies and regulations in order to assess their role in addressing serious global predicaments.

The writer is researcher at the L.P. Cookingham Urban Affairs Institute, Kansas City, MO, USA.

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