Food irradiation is a safe and effective form of processing. Food irradiation has been approved in 40 countries including the United States, Japan, China, France and Holland. Irradiated foods will be clearly labeled so that consumers can make an informed choice.

Some of the benefits of this food processing technique include:

• The food does not become radioactive

• Extended shelf life of some products.

• Less food spoilage.

• Disease-causing microorganisms are reduced or eliminated

• Less need for pesticides.

• Less need for some additives, such as preservatives and antioxidants.

• Lower risk of importing or exporting insect pests hidden inside food products.

• Reduced need for toxic chemical treatments, such as those used to kill bacteria found in some spices.

• The irradiation process produces very little chemical change in food.  None of the changes known to occur have been found to be harmful or dangerous.

• As an alternative to current treatment for disinfecting imported fruits, grains and vegetables, which uses an ozone-depleting gas.

• Reduced sprouting in potatoes and onions.

However, this does not mean that food irradiation is the "ultimate solution" for all food problems.

There are some limitations:

• It can be used only on a limited range of foods -- Fresh fruits (papaya, citrus, apples, strawberries, lychee, rambutan, cherimoya, tomatoes); spices and dried vegetables; frog legs; onions and garlic; chicken; fermented pork sausages; dried fish; and red meat.  The limitation on foods that can be irradiated is a political, not a technical issue, and depends on approval for different organizations.

• It is still a relatively expensive technology -- Broken down, irradiation costs range from US $10 to $15 per ton for a low-dose application, up to US $100 to $250 per ton for a high-dose application.  These costs are competitive with alternative treatments such as canning, freezing, pasteurization, refrigeration, and fumigation

• Radiation doses at the levels recommended will not kill all microorganisms -- Typically 90% may be destroyed; this means that the food still has be treated with care, otherwise the remaining organisms will reproduce rapidly.

Regulation of Irradiated Food

The Food and Drug Administration (FDA) regulates all aspects of irradiation: what products it can be used on, what dose can be used And how those products are labeled. The U.S. Department of Agriculture (USDA) is responsible for the inspection and monitoring of irradiated meat and poultry products and for the enforcement of FDA regulations concerning those products. Since 1986, all irradiated products must carry the international symbol called a radura, which resembles a stylized flower.

FDA requires that both the logo and statement appear on packaged foods, bulk containers of unpackaged foods, on placards at the point of purchase (for fresh produce), and on invoices for irradiated ingredients and products sold to food processors.

Processors may add information explaining why irradiation is used; for example, treated with irradiation to inhibit spoilage or treated with irradiation instead of chemicals to control insect infestation.

Dosage in Irradiated Food

The measurement of radiation dose is referred to as dosimetry and it involves exposing dosimeters jointly with the treated food item. Dosimeters are small components attached to the irradiated product made of materials that when exposed to ionizing radiation change specific measurable physical attributes to a degree that can be correlated to the dose received. Modern dosimeters are made of a range of materials such as alanine pellets, Perspex blocks, radio chromic films, as well as special solutions and other materials. These dosimeters are used in combination with specialized read out devices.

Low Dose Applications (up to 1 kGy

• Sprout inhibition in bulbs and tubers 0.03-0.15 kGy

• Delay in fruit ripening 0.25-0.75 kGy

• Insect disinfestations including, quarantine treatment and elimination of food borne parasites 0.07-1.00 kGy

Medium Dose Applications (1 kGy to 10 kGy)

• Reduction of spoilage microbes to improve shelf-life of meat, poultry and seafoods under refrigeration 1.50-3.00 kGy

• Elimination of pathogenic microbes in fresh and frozen meat, poultry and seafoods 3.00-7.00 kGy

• Reducing number of microorganisms in spices to improve hygenic quality 10.00 kGy

High Dose Applications (above 10 kGy)

• Sterilization of packaged meat, poultry and their products which are shelf stable without refrigeration. 25.00-70.00 kGy

• Sterilization of Hospital diets 25.00-70.00 kGy

• Product improvement as increased juice yield or improved re-hydration

It is important to note that the FDA and other regulators around the world above those currently permit these doses for these food items.

Food irradiation facilities

Industrial food irradiation facilities must be licensed, regulated and inspected by national radiological safety and health authorities, many of who base their rules upon irradiation standards and codes of practice jointly established by the IAEA, FAO and WHO. The common features of all commercial irradiation facilities are the irradiation room and a system to transport the food into and out of the room. The major structural difference between this type of plant and any other industrial building is the concrete shielding (1.5 Ð 1.8 metres thick) surrounding the irradiation room, which ensures that ionizing radiation does not escape to the outside of the room. In the case of a gamma irradiator, the radio nuclide source

Continuously emits radiation and when not being used to treat food must be stored in a water pool (usually 6 metres in depth). Known as one of the best shields against radiation energy, water absorbs the radiation energy and protects

Workers from exposure if they must enter the room. In contrast to gamma irradiators, machines producing high-energy electrons operate on electricity and can be switched off.

The transport system employed in a large food irradiation facility is similar to that used for sterilization of medical products and can be either a conveyor or a rail system. In a gamma irradiator, the size of the containers in which the food is moved through the irradiation chamber can be varying.

Accidents involving irradiation facilities

Medical sterilization facilities have been operated in this country for more than 30 years, without a fatal accident. Over 100 such facilities are currently licensed, along with at least that many medical radiation treatment centers, and bone marrow transplant centers (which also use Cobalt 60 to irradiate patients). No events have been documented in this country that led to exposure of the population at large to radioactivity. In other countries, a small number of fatal incidents have been documented in which a worker by-passed multiple safety steps to enter the chamber while the source were exposed, resulting in a severe or even lethal radiation injury to themselves.

Adoption of the Technology

Although some food radiation treatments have been approved in the U.S. since 1963, there has been only infrequent use in test markets other than use on spices. The food industry is slow to invest in this technology because of uncertainty over the public acceptance of food. In 1986, 2 metric tons of mangoes irradiated in Puerto Rico were test marketed in Miami, FL. In 1987, irradiated Hawaiian papayas were tested in Anaheim and Irvine, CA. These test market studies as well as others in France, Argentina and South Africa indicated good consumer acceptance and willingness to buy.

Worldwide, over 30 countries approve some form of irradiation and many groups of consumers readily accept these products. As of 1986, Japan irradiated over 10,000 pounds of potatoes annually. The Netherlands irradiated 2 tons of food daily, and Belgium irradiated 1 ton daily. South Africa routinely irradiates mangoes, papaya, and other vegetables. Canada has a facility dedicated to irradiating potatoes.

Safety and Concerns

The term irradiation often evokes fears of nuclear radioactivity and cancer among consumers. The process seems frightening because it is powerful and invisible. Consequently, questions and concerns exist, particularly about the safety or wholesomeness of irradiated food.

One major concern is the irradiated foods radioactive? The answer is no but the similarity between the two words is confusing. It is physically impossible for irradiated food to be radioactive just as your teeth are not radio-active after you have had a dental X-ray. Irradiation is radiant energy. It disappears when the energy source is removed.

Another frequent concerns is toxicity of such foods. Over the past 30 years, researchers in several countries have evaluated irradiated foods for chemical products (radiolytic products) which may have formed. The toxicity of those products has been studied also.

Sometimes, public interest groups and public health experts expresses that irradiation, as a non-preventive measure, might disguise or otherwise divert attention away from poor working conditions, sanitation, and poor food-handling procedures that lead to contamination in the first place. However, similar or even identical concerns had been expressed when the heat-pasteurization of milk had become compulsory; in the contrary to such fears, dairy operations and hygiene have been improved until today.

Processors of irradiated food are subject to all existing regulations, inspections, and potential penalties regarding plant safety and sanitization; including fines, recalls, and criminal prosecutions. Furthermore, while food irradiation can in some cases maintain the quality of certain perishable food for a longer period of time, it cannot undo spoilage effects that occur prior to irradiation. Irradiation can therefore not be successfully used to mask quality issues other than pathogens.

Worker Safety

Experience over more than 40 years in the field of radiation processing has shown that such technology is generally safely used. The steady improvement in the design of such facilities and careful selection and training of operators has contributed to a very good safety record. Nevertheless, there have been instances, as in Italy in 1975, in Norway in 1982 and in El Salvador in 1989, when safety systems have been circumvented and serious radiological accidents involving workers at the facilities have ensued.

The safety of irradiation facilities is regulated by the United Nations International Atomic Energy Agency and monitored by the different national Nuclear Regulatory Commissions. The incidents that have occurred in the past are documented by the agency and thoroughly analyzed to determine root cause and improvement potential. Such improvements are then mandated to retrofit existing facilities and future design.

National and International regulations on the levels and types of energy used to irradiate food generally set standards that prevent the possibility of inducing radioactivity in treated foods. Care must be taken not to expose the operators and the environment to radiation. Interlocks and safeguards are mandated to minimize this risk. Nevertheless there have been radiation related deaths and injury amongst workers of such facilities, many of them caused by the operators themselves overriding the interlocks.

The Disadvantages of Food Irradiation:

• Irradiation can kill some bacteria, those most sensitive to it, but it never removes toxins already deposited in the food.

• Some of the organoleptic properties are affected especially for herbs, spices, and essential oils.

• Irradiation fails to eliminate pesticide residues and other chemical hazards in food.

• It reduces the content of several key nutrients such as Vitamin E (~15-30 %); Thiamin (~10-25%); Vitamin C (5-15%); Riboflavin (~7-10%); Pyridoxine (~10-20%); Vitamin B12 (~15-20%). Other nutrients are also affected however the results are less consistent.

• It creates radiolytic products with unknown short term or long term safety effects.

• Formation of cholesterol oxides and fatty acid epoxidation and other oxidation products (aldehydes, esters, ketones etc.) posing safety concerns.

• Aggregation of certain proteins has been found for high protein commodities.

• Is ineffective against viruses.

Alternatives to Food Irradiation

Other methods to reduce different pathogens in food include heat-pasteurization, Ultra-high temperature processing, UV radiation, Ozone or fumigation with ethylene oxide.

Insect pests can also be eliminated by fumigation with methyl bromide or aluminum phosphine, vapour heat, forced hot air, hot water dipping, or cold treatment. However, the Mango weevil sitting in the stone of the fruit can only be reached by ionizing radiation.

Other methods to extend shelf life of food items include modified atmosphere packaging, carbon monoxide, dehydration, vacuum packaging, freezing and flash freezing as well as chemical additives. However, such methods are not effective for products already deep-frozen where only ionizing radiation can penetrate the product (without re-thawing).

Some people argue that the best alternative to food irradiation to reduce pathogens is in good agricultural practices. For example, farmers and processing plants should improve sanitation practices, water used for irrigation and processing should be regularly tested for E. coli, and production plants should be routinely inspected. Concentrated animal feeding operations near farmland where produce is grown should be regulated.

However, such methods as also practiced in organic farming can only reduce the extend of the load with microorganisms of all kind; a residual flora including pathogen germs will always persist; and processing by ionizing radiation could be the ultimate measure (as a CCP under a HACCP-concept) to practically eliminate such risks.

Packaging of Irradiated Foods

With the exception of such applications as sprout inhibition in potatoes or onions, insect disinfestations in bulk grains, or delay of post-harvest ripening of fruits, irradiation of foodstuffs is usually carried out on packaged food items. There may be different reasons for this: prevention of microbial reinfection or insect exposure, prevention of water loss, exclusion of oxygen, prevention of mechanical damage during transport, or simply improved handling and marketing. The packaging material used must not release radiation-induced reaction products or additives onto the food, nor should it lose functional qualities such as mechanical strength, seal stability, or impermeability to water upon irradiation.

Irradiated materials used to package foods

Plastic films laminated with aluminium foil are routinely sterilized by radiation as part of the manufacturing process. They are used for hermetically sealed Òbag-in-a-boxÓ products, such as tomato paste, fruit juices, and wines. Other aseptic packaging materials, dairy product packaging, single-serving containers (for example, for cream), and wine bottle corks are also routinely sterilized by irradiation prior to filling and sealing to prevent product contamination. Other types of materials used to wrap food or other products also are routinely processed by radiation in many countries. The radiation process is used to "cross-linkÓ the materialÕs polymer chains for greater strength and heat resistance, and for producing plastics with special properties (for example, heat-shrink wrap).