Food irradiation
Encyclopedia
Food irradiation is the process of exposing food to ionizing radiation
to destroy microorganism
s, bacteria
, virus
es, or insect
s that might be present in the food. Further applications include sprout inhibition, delay of ripening, increase of juice yield, and improvement of re-hydration. Irradiated food does not become radioactive, but in some cases there may be subtle chemical changes.
Irradiation
is a more general term of the exposure of materials to radiation to achieve a technical goal (in this context "ionizing radiation" is implied). As such it is also used on non-food items, such as medical device
s, plastics, tubes for gas pipelines, hoses for floor heating, shrink-foils for food packaging, automobile parts, wires and cables (isolation), tires, and even gemstones.
Food irradiation acts by damaging the target organism's DNA
beyond its ability to repair
. Microorganisms can no longer proliferate and continue their malignant or pathogenic activities. Spoilage-causing microorganisms cannot continue their activities. Insects do not survive, or become incapable of reproduction. Plants cannot continue their natural ripening processes.
The energy density per atomic transition of ionizing radiation is very high; it can break apart molecules and induce ionization
, which is not achieved by mere heating. This is the reason for both new effects and new concerns. The treatment of solid food by ionizing radiation can provide an effect similar to heat pasteurization of liquids, such as milk. The use of the term "cold pasteurization" to describe irradiated foods is controversial, since pasteurization and irradiation are fundamentally different processes.
Food irradiation is currently permitted by over 50 countries, and the volume of food treated is estimated to exceed 500,000 metric tons annually worldwide.
s and spice
s, are irradiated at sufficient doses (five kilograys
or more) to reduce the microbial counts by several orders of magnitude; such ingredients do not carry over spoilage or pathogen microorganisms into the final product. It has also been shown that irradiation can delay the ripening of fruits or the sprouting of vegetables.
Insect pests can be sterilized
(be made incapable of proliferation) using irradiation at relatively low doses. In consequence, the United States Department of Agriculture
(USDA) has approved the use of low-level irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to a number of insect pests, including fruit flies and seed weevils; the U.S. Food and Drug Administration (FDA) has cleared among a number of other applications the treatment of hamburger patties to eliminate the residual risk of a contamination by a virulent E. coli. The United Nations Food and Agricultural Organization (FAO) has passed a motion to commit member states to implement irradiation technology for their national phytosanitary programs; the General assembly of the International Atomic Energy Agency
(IAEA) has urged to make wider use of the irradiation technology. Additionally, the USDA has made a number of bi-lateral agreements with developing countries to facilitate the imports of exotic fruits and to simplify the quarantine procedures.
The European Union
has regulated processing of food by ionizing radiation in specific directives since 1999; the relevant documents and reports are accessible online.
The "implementing" directive contains a "positive list" permitting irradiation of only dried aromatic herbs, spices, and vegetable seasonings.
However, any Member State is permitted to maintain previously granted clearances or to add new clearance as granted in other Member States, in the case the EC's Scientific Committee on Food (SCF) has given a positive vote for the respective application. Presently, six Member States (Belgium, France, Italy, Netherlands, Poland, United Kingdom) have adopted such provisions.
Because of the "Single Market
" of the EC, any food – even if irradiated – must be allowed to be marketed in any other Member State even if a general ban of food irradiation prevails, under the condition that the food has been irradiated legally in the state of origin.
Furthermore, imports into the EC are possible from third countries if the irradiation facility had been inspected and licensed by the EC and the treatment is legal within the EC or some Member state.
The Scientific Committee on Food (SCF) of the EC has given a positive vote on eight categories of food to be irradiated. However, in a compromise between the European Parliament
and the European Commission
, only dried aromatic herbs, spices, and vegetable seasonings can be found in the positive list. The European Commission was due to provide a final draft for the positive list by the end of 2000; however, this failed because of a veto from Germany and a few other Member States. In 1992, and in 1998 the SCF voted "positive" on a number of irradiation applications that had been allowed in some member states before the EC Directives came into force, to enable those member states to maintain their national authorizations.
In 2003, when Codex Alimentarius
was about to remove any upper dose limit for food irradiation, the SCF adopted a "revised opinion", which, in fact, was a re-confirmation and endorsement of the 1986 opinion. The opinion denied cancellation of the upper dose limit, and required that before the actual list of individual items or food classes (as in the opinions expressed in 1986, 1992 and 1998) can be expanded, new individual studies into the toxicology of each of such food and for each of the proposed dose ranges are requested. The SCF has subsequently been replaced by the new European Food Safety Authority
(EFSA), which has not yet ruled on the processing of food by ionizing radiation.
Other countries, including New Zealand, Australia, Thailand, India, and Mexico, have permitted the irradiation of fresh fruits for fruit fly
quarantine purposes, amongst others. Such countries as Pakistan and Brazil have adopted the Codex Alimentarius Standard on Irradiated Food without any reservation or restriction: i.e., any food may be irradiated to any dose.
(Gy). One gray of radiation is equal to 1 joule of energy absorbed per kilogram of food material. In radiation processing of foods, the doses are generally measured in kilograys (kGy, 1,000 Gy).
and involves exposing dosimeter
s 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 (PMMA) blocks, and radiochromic films, as well as special solutions and other materials. These dosimeters are used in combination with specialized read out devices. Standards that describe calibration and operation for radiation dosimetry, as well as procedures to relate the measured dose to the effects achieved and to report and document such results, are maintained by the American Society for Testing and Materials (ASTM international) and are also available as ISO/ASTM standards.
These doses are above those currently permitted for these food items by the FDA and other regulators around the world. The Codex Alimentarius
Standard on Irradiated Food does not specify any upper dose limit. NASA
is authorized to sterilize frozen meat for astronauts at doses of 44 kGy as a notable exception.
Irradiation treatments are also sometimes classified as radappertization
, radicidation
and radurization
.
s in the gamma part of the electromagnetic spectrum
. The radiation is obtained through the use of radioisotopes, generally cobalt-60
or, in theory, caesium-137
. Cobalt-60 is bred from cobalt-59 using neutron irradiation in specifically designed nuclear reactors. Caesium-137 is recovered during the processing of spent nuclear fuel
. Because this technology – except for military applications – is not commercially available, insufficient quantities of it are available on the global isotope markets for use in large scale, commercial irradiators. Presently, caesium-137 is used only in small hospital units to treat blood before transfusion to prevent Graft-versus-host disease
.
Food irradiation using cobalt-60 is the preferred method by most processors, because the deeper penetration enables administering treatment to entire industrial pallets or totes, reducing the need for material handling. A pallet or tote is typically exposed for several minutes to hours depending on dose. Radioactive material must be monitored and carefully stored to shield workers and the environment from its gamma rays. During operation this is achieved by substantial concrete shields. With most designs the radioisotope can be lowered into a water-filled source storage pool to allow maintenance personnel to enter the radiation shield. In this mode the water in the pool absorbs the radiation. Other uncommonly used designs feature dry storage by providing movable shields that reduce radiation levels in areas of the irradiation chamber.
One variant of gamma irradiators keeps the cobalt-60 under water at all times and lowers the product to be irradiated under water in hermetic bells. No further shielding is required for such designs.
s are photon radiation of a wide energy spectrum and an alternative to isotope based irradiation systems. X-rays are generated by colliding accelerated electrons with a dense material (target) such as tantalum
or tungsten
in a process known as bremsstrahlung
-conversion. X-ray irradiators are scalable and have deep penetration comparable to Co-60, with the added benefit that the electronic source stops radiating when switched off. They also permit dose uniformity, but these systems generally have low energetic efficiency during the conversion of electron energy to photon radiation requiring much more electrical energy than other systems. Like most other types of facilities, X-ray systems rely on concrete shields to protect the environment and workers from radiation.
Nominal X-ray energy is usually limited to 5 MeV; the USA has provisions for up to 7.5 MeV, which increases conversion efficiency. Another development is the availability of electron accelerators with extremely high power output, up to 1,000 kW beam. At a conversion efficiency of up to 12%, the X-ray power may reach (including filtering and other losses) 100 kW; This power would be equivalent to a gamma facility with Co-60 of about 6.5 MCi.
to the U.S. in 2008 and mango
in 2009; and has received approval for citrus, star fruit
and Manzano chili
. Some Asian countries hold bilateral agreements to irradiate exotic fruits for quarantine purposes and export it to the USA.
The cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions, i.e., packaging and stacking requirements, construction costs, financing arrangements, and other variables particular to the situation. Irradiation is a capital-intensive technology requiring a substantial initial investment, ranging from $1 million to $5 million. In the case of large research or contract irradiation facilities, major capital costs include a radiation source (cobalt-60), hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), land (1 to 1.5 acres), radiation shield, and warehouse. Operating costs include salaries (for fixed and variable labor), utilities, maintenance, taxes/insurance, cobalt-60 replenishment, general utilities, and miscellaneous operating costs.
Treatment costs vary as a function of dose and facility usage. Low dose applications such as disinfestation of fruit range between US$0.01/lbs and US$0.08/lbs while higher dose applications can cost as much as US$0.20/lbs.
Consumer organizations, environmentalist groups, and opponents to food irradiation refer to some studies suggesting that a large part of the public questions the safety of irradiated foods, and will not buy foods that have been irradiated.
On the other hand, other studies indicate the number of consumers concerned about the safety of irradiated food has decreased in the last 10 years and continues to be less than the number of those concerned about pesticide residues, microbiological contamination, and other food related concerns. Such numbers are comparable to those of people with no concern about food additives and preservatives. Consumers, given a choice and access to irradiated products, appear ready to buy it in considerably large numbers.
represents the global standard in particular under the WTO-agreement, member states are free to convert those standards into national regulations. With regard to labelling of irradiated food, detailed rules are published at CODEX-STAN – 1 (2005) labelling of prepacked food.
The provisions are that any "first generation" product must be labeled "irradiated" as any product derived directly from an irradiated raw material; for ingredients the provision is that even the last molecule of an irradiated ingredient must be listed with the ingredients even in cases where the unirradiated ingredient does not appear on the label. The RADURA-logo is optional; several countries use a graphical version that differs from the Codex-version.
In the U.S., as in many other countries, irradiated food must be labeled as "Treated with irradiation" or "Treated by radiation" and require the use of the Radura
symbol at the point of sale. The meaning of the label is not consistent. The amount of irradiation used can vary and since there are no published standards, the amount of pathogens affected by irradiation can vary as well. In addition, there are no regulations regarding the levels of pathogen reduction that must be achieved. Food that is processed as an ingredient by a restaurant or food processor is exempt from the labeling requirement in the US; other countries follow the Codex Alimentarius provision to label irradiated ingredients down to the last molecule (cf. EU).
FDA is currently proposing a rule that in some cases would allow certain irradiated foods to be marketed without any labeling at all. Under the new rules, only those irradiated foods in which the irradiation causes a material change in the food, or a material change in the consequences that may result from the use of the food, would bear the Radura symbol and the term "irradiated", or a derivative thereof, in conjunction with explicit language describing the change in the food or its conditions of use. In the same rule FDA is proposing to permit a firm to use the terms "electronically pasteurized" or "cold pasteurized" in lieu of "irradiated", provided it notifies the agency that the irradiation process being used meets the criteria specified for use of the term "pasteurized".
Food irradiation is sometimes referred to as "cold pasteurization" or "electronic pasteurization" because ionizing the food does not heat the food to high temperatures during the process, as in heat-pasteurization (at a typical dose of 10 kGy, food that is physically equivalent to water would warm by about 2.5 °C). The treatment of solid food by ionizing radiation can provide an effect similar to heat pasteurization of liquids, such as milk. The use of the term "cold pasteurization" to describe irradiated foods is controversial, because pasteurization and irradiation are fundamentally different processes, although the intended end results can in some cases be similar.
Consumer perception of foods treated with irradiation is more negative than those processed by other means. "People think the product is radioactive," said Harlan Clemmons, president of Sadex, a food irradiation company based in Sioux City, Iowa.
This may be understood as a tool for government authorities to enforce existing labeling standards and to bolster consumer confidence. The European Union is particularly strict in enforcing irradiation labeling requiring its member countries to perform tests on a cross section of food items in the market-place and to report to the European Commission; the results are published annually in the OJ of the European Communities.
Food irradiation in the United States is primarily regulated by the FDA since it is considered a food additive. Other federal agencies that regulate aspects of food irradiation include:
Each new food is approved separately with a guideline specifying a maximum dosage; in case of quarantine applications the minimum dose is regulated. Packaging materials containing the food processed by irradiation must also undergo approval.
The Radura logo as regulated by FDA is slightly different from the international version as proposed in Codex Alimentarius.
Consumer advocacy groups such as Public Citizen
or Food and Water Watch
maintain that the safety of irradiated food is not proven, in particular long-term studies are still lacking, and strongly oppose the use of the technology.
A report of fatal incidences with pet food in Australia led to some rumours and speculation about the safety of irradiated food and a nationwide recall. In the Australian case, sixteen cats were reported to have been euthanized after severe paralysis subsequent to being fed a certain cat food. The company issuing a recall stated that the problem only occurred with Australian pet-food. The company speculated this was due to irradiating the pet-food. The Australian Quarantine Inspection Services (AQIS) (at that time) required the irradiation to a minimum dose of 50 kGy or heating of imported dry food. After the incident, the pet food manufacturer created a compassion fund for pet owners. The cause of the cat illness is not yet clearly understood and is still under investigation and verification. Vitamin A depletion was not confirmed in the affected cats. Researchers from Wisconsin University announcing their conference presentation said in the published abstract: "Here, we show that cats fed an irradiated diet during gestation developed a severe neurologic disease resulting from extensive myelin vacuolation and subsequent demyelination."
Radiation processing of imported cat food has now been banned in Australia. Previously it had been a mandatory requirement for imports including dry and semi-moist food to be irradiated at a minimum dose of 50 kGy or to be heated to a temperature of 100 °C (212 °F) for a minimum of 30 minutes. The AQIS – having jurisdiction on quarantine issues – announced on June 6, 2009 that the alternative of radiation processing for cat food is no longer acceptable and that irradiated dog food needs to be labeled by "Must not be fed to cats". AQIS in its announcement refers to recently published scientific studies and reminds importers of their responsibility to regularly check whether new scientific results could have any implication for their products. Australia does not permit food irradiation, generally; at present only dog feed may be irradiated upon import, but must be labelled 'do not feed to cats'. Dr. G. Child has published a report of the clinical signs and outcomes of those cats. The authors point to epidemiological and to toxicological studies that are still underway. It is not yet clear which mechanism and what changes in irradiated pet food cause damages in the white matter of spinal cord and brain.
in the first place.
Concerns and objections include the possibility that food irradiation might do any of the following:
Processors of irradiated food are subject to all existing regulations, inspections, and potential penalties regarding plant safety and sanitation; including fines, recalls, and criminal prosecutions. But critics of the practice claim that a lack of regulatory oversight (such as regular food processing plant inspections) necessitates irradiation.
While food irradiation can in some cases maintain the quality (i.e. general appearance and "inner" quality) of certain perishable food for a longer period of time, it cannot undo spoilage that occurred prior to irradiation. Irradiation cannot successfully be used to mask quality issues other than pathogens. As with heat pasteurization (for example, milk), processing by ionizing radiation can contribute to eliminate pathogen risks from solid food (example meat or lettuce). For comparison, milk heat pasteurization is not being alleged to be a method "to cover up poor food quality"; consequently, food irradiation should not be accused to serve such criminal purposes. Under a HACCP-concept (Hazard Analysis and Critical Control Point) radiation processing can serve and contribute as an ultimate critical control point before the food reaches the consumer.
Opponents of food irradiation and consumer activists argue that the final proof is missing that irradiated food is "safe" (i.e. not unwholesome) and that the lack of long-term studies should be a further reason not to permit food irradiation. Opponents also refer to a number of scientific publications reporting significant negative effects of irradiated food, for example
However, those experiments could be either not verified in later experiments, could not be clearly attributed to the radiation effect, or could be attributed to an inappropriate design of the experiment etc.
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.
Care must be taken not to expose the operators and the environment to radiation or radioactive contamination. 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. "Ordinary" occupational safety regulations also apply to radiation processing facilities; the radiation aspects are typically excluded and supervised by special authorities.
An incident in Decatur, Georgia
where water soluble caesium-137 leaked into the source storage pool requiring NRC
intervention has led to near elimination of this radioisotope; it has been replaced by the more costly, non-water soluble cobalt-60.
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, and, hence, excluding the risk to workers and the environment.
, ultra-high temperature processing, UV irradiation
, ozone
, Pascalization
, Thermization
or fumigation with ethylene oxide
.
For quarantine purposes, insect pests can also be eliminated by fumigation with methyl bromide or aluminium phosphine, vapour heat, forced hot air, hot water dipping, or cold treatment.
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.
Opponents of food irradiation and consumer activists (cf. Public Citizen) maintain that the best alternative to food irradiation to reduce pathogens is in good agricultural practices. 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.
Proponents of food irradiation have said that practices of organic farming can only reduce the extent of the microorganism load. They assert that residual flora including pathogen germs always persist, and that processing by ionizing radiation could be the ultimate measure (as a CCP under a HACCP-concept) to practically eliminate such risks.
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...
to destroy microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s, bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es, or insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s that might be present in the food. Further applications include sprout inhibition, delay of ripening, increase of juice yield, and improvement of re-hydration. Irradiated food does not become radioactive, but in some cases there may be subtle chemical changes.
Irradiation
Irradiation
Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve a specific purpose, rather than radiation exposure to...
is a more general term of the exposure of materials to radiation to achieve a technical goal (in this context "ionizing radiation" is implied). As such it is also used on non-food items, such as medical device
Medical device
A medical device is a product which is used for medical purposes in patients, in diagnosis, therapy or surgery . Whereas medicinal products achieve their principal action by pharmacological, metabolic or immunological means. Medical devices act by other means like physical, mechanical, thermal,...
s, plastics, tubes for gas pipelines, hoses for floor heating, shrink-foils for food packaging, automobile parts, wires and cables (isolation), tires, and even gemstones.
Food irradiation acts by damaging the target organism's DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
beyond its ability to repair
DNA repair
DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1...
. Microorganisms can no longer proliferate and continue their malignant or pathogenic activities. Spoilage-causing microorganisms cannot continue their activities. Insects do not survive, or become incapable of reproduction. Plants cannot continue their natural ripening processes.
The energy density per atomic transition of ionizing radiation is very high; it can break apart molecules and induce ionization
Ionization
Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...
, which is not achieved by mere heating. This is the reason for both new effects and new concerns. The treatment of solid food by ionizing radiation can provide an effect similar to heat pasteurization of liquids, such as milk. The use of the term "cold pasteurization" to describe irradiated foods is controversial, since pasteurization and irradiation are fundamentally different processes.
Food irradiation is currently permitted by over 50 countries, and the volume of food treated is estimated to exceed 500,000 metric tons annually worldwide.
Processing of food by ionizing radiation
By irradiating food, depending on the dose, some or all of the harmful bacteria and other pathogens present are killed. This prolongs the shelf-life of the food in cases where microbial spoilage is the limiting factor. Some foods, e.g., herbHerb
Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...
s and spice
Spice
A spice is a dried seed, fruit, root, bark, or vegetative substance used in nutritionally insignificant quantities as a food additive for flavor, color, or as a preservative that kills harmful bacteria or prevents their growth. It may be used to flavour a dish or to hide other flavours...
s, are irradiated at sufficient doses (five kilograys
Gray (unit)
The gray is the SI unit of absorbed radiation dose of ionizing radiation , and is defined as the absorption of one joule of ionizing radiation by one kilogram of matter ....
or more) to reduce the microbial counts by several orders of magnitude; such ingredients do not carry over spoilage or pathogen microorganisms into the final product. It has also been shown that irradiation can delay the ripening of fruits or the sprouting of vegetables.
Insect pests can be sterilized
Sterility (physiology)
Sterility is the physiological inability to effect sexual reproduction in a living thing, members of whose kind have been produced sexually. The term may be used in reference to* types of organism, such as the mule, a sterile hybrid;...
(be made incapable of proliferation) using irradiation at relatively low doses. In consequence, the United States Department of Agriculture
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
(USDA) has approved the use of low-level irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to a number of insect pests, including fruit flies and seed weevils; the U.S. Food and Drug Administration (FDA) has cleared among a number of other applications the treatment of hamburger patties to eliminate the residual risk of a contamination by a virulent E. coli. The United Nations Food and Agricultural Organization (FAO) has passed a motion to commit member states to implement irradiation technology for their national phytosanitary programs; the General assembly of the International Atomic Energy Agency
International Atomic Energy Agency
The International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...
(IAEA) has urged to make wider use of the irradiation technology. Additionally, the USDA has made a number of bi-lateral agreements with developing countries to facilitate the imports of exotic fruits and to simplify the quarantine procedures.
The European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
has regulated processing of food by ionizing radiation in specific directives since 1999; the relevant documents and reports are accessible online.
The "implementing" directive contains a "positive list" permitting irradiation of only dried aromatic herbs, spices, and vegetable seasonings.
However, any Member State is permitted to maintain previously granted clearances or to add new clearance as granted in other Member States, in the case the EC's Scientific Committee on Food (SCF) has given a positive vote for the respective application. Presently, six Member States (Belgium, France, Italy, Netherlands, Poland, United Kingdom) have adopted such provisions.
Because of the "Single Market
Single market
A single market is a type of trade bloc which is composed of a free trade area with common policies on product regulation, and freedom of movement of the factors of production and of enterprise and services. The goal is that the movement of capital, labour, goods, and services between the members...
" of the EC, any food – even if irradiated – must be allowed to be marketed in any other Member State even if a general ban of food irradiation prevails, under the condition that the food has been irradiated legally in the state of origin.
Furthermore, imports into the EC are possible from third countries if the irradiation facility had been inspected and licensed by the EC and the treatment is legal within the EC or some Member state.
The Scientific Committee on Food (SCF) of the EC has given a positive vote on eight categories of food to be irradiated. However, in a compromise between the European Parliament
European Parliament
The European Parliament is the directly elected parliamentary institution of the European Union . Together with the Council of the European Union and the Commission, it exercises the legislative function of the EU and it has been described as one of the most powerful legislatures in the world...
and the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
, only dried aromatic herbs, spices, and vegetable seasonings can be found in the positive list. The European Commission was due to provide a final draft for the positive list by the end of 2000; however, this failed because of a veto from Germany and a few other Member States. In 1992, and in 1998 the SCF voted "positive" on a number of irradiation applications that had been allowed in some member states before the EC Directives came into force, to enable those member states to maintain their national authorizations.
In 2003, when Codex Alimentarius
Codex Alimentarius
The Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
was about to remove any upper dose limit for food irradiation, the SCF adopted a "revised opinion", which, in fact, was a re-confirmation and endorsement of the 1986 opinion. The opinion denied cancellation of the upper dose limit, and required that before the actual list of individual items or food classes (as in the opinions expressed in 1986, 1992 and 1998) can be expanded, new individual studies into the toxicology of each of such food and for each of the proposed dose ranges are requested. The SCF has subsequently been replaced by the new European Food Safety Authority
European Food Safety Authority
The European Food Safety Authority is an agency of the European Union that provides independent scientific advice and communication on existing and emerging risks associated with the food chain, created by European Regulation 178/2002....
(EFSA), which has not yet ruled on the processing of food by ionizing radiation.
Other countries, including New Zealand, Australia, Thailand, India, and Mexico, have permitted the irradiation of fresh fruits for fruit fly
Drosophilidae
Drosophilidae is a diverse, cosmopolitan family of flies, which includes fruit flies. Another family of flies called Tephritidae also includes fruit flies. The best known species of Drosophilidae is Drosophila melanogaster, within the genus Drosophila, and this species Is used extensively for...
quarantine purposes, amongst others. Such countries as Pakistan and Brazil have adopted the Codex Alimentarius Standard on Irradiated Food without any reservation or restriction: i.e., any food may be irradiated to any dose.
Radiation absorbed dose
"Dose" is the physical quantity governing the radiation processing of food, relating to the beneficial effects to be achieved.Unit of measure for irradiation dose
The dose of radiation is measured in the SI unit known as the grayGray (unit)
The gray is the SI unit of absorbed radiation dose of ionizing radiation , and is defined as the absorption of one joule of ionizing radiation by one kilogram of matter ....
(Gy). One gray of radiation is equal to 1 joule of energy absorbed per kilogram of food material. In radiation processing of foods, the doses are generally measured in kilograys (kGy, 1,000 Gy).
Dosimetry
The measurement of radiation dose is referred to as dosimetryDosimetry
Radiation dosimetry is the measurement and calculation of the absorbed dose in matter and tissue resulting from the exposure to indirect and direct ionizing radiation...
and involves exposing dosimeter
Dosimeter
Dosimeters measure an individual's or an object'sexposure to something in the environment — particularly to a hazard inflicting cumulative impact over long periods of time, or over a lifetime...
s jointly with the treated food item. Dosimeters are small components attached to the irradiated product made of materials that, when exposed to ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...
, 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 (PMMA) blocks, and radiochromic films, as well as special solutions and other materials. These dosimeters are used in combination with specialized read out devices. Standards that describe calibration and operation for radiation dosimetry, as well as procedures to relate the measured dose to the effects achieved and to report and document such results, are maintained by the American Society for Testing and Materials (ASTM international) and are also available as ISO/ASTM standards.
Applications
On the basis of the dose of radiation the application is generally divided into three main categories: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 disinfestation 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 prolong shelf-life of meat, poultry and seafoods under refrigeration 1.50–3.00 kGy
- Reduction of pathogenic microbes in fresh and frozen meat, poultry and seafoods 3.00–7.00 kGy
- Reducing the number of microorganisms in spices to improve hygienic quality 10.00 kGy
High dose applications (above 10 kGy)
- Sterilization of packaged meat, poultry, and their products that 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
These doses are above those currently permitted for these food items by the FDA and other regulators around the world. The Codex Alimentarius
Codex Alimentarius
The Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
Standard on Irradiated Food does not specify any upper dose limit. NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
is authorized to sterilize frozen meat for astronauts at doses of 44 kGy as a notable exception.
Irradiation treatments are also sometimes classified as radappertization
Radappertization
Radappertization is a form of food irradiation which applies a dose of ionizing radiation sufficient to reduce the number and activity of viable microorganisms to such an extent that very few, if any, are detectable in the treated food by any recognized method...
, radicidation
Radicidation
Radicidation is a specific case of food irradiation where the dose of ionizing radiation applied to the food is sufficient to reduce the number of viable specific non-spore-forming pathogenic bacteria to such a level that none are detectable when the treated food is examined by any recognized...
and radurization
Radurization
Radurization is the application to food irradiation to foods using a dose of ionizing radiation sufficient to enhance its keeping quality by causing a substantial decrease in numbers of viable specific spoilage microorganisms. The required dose is in the range of 0.4 - 10 kGy.on what food product...
.
Table of the history of food irradiation
- 1895 Wilhelm Conrad RöntgenWilhelm Conrad RöntgenWilhelm Conrad Röntgen was a German physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range today known as X-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901....
discovers X-rays ("bremsstrahlung", German for radiation produced by deceleration) - 1896 Antoine Henri Becquerel discovers natural radioactivity; Minck proposes the therapeutic use
- 1904 Samuel Prescott describes the bactericide effects Massachusetts Institute of TechnologyMassachusetts Institute of TechnologyThe Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
(MIT) - 1906 Appleby & Banks: UK patent to use radioactive isotopes to irradiate particulate food in a flowing bed
- 1918 Gillett: U.S. Patent to use X-rays for the preservation of food
- 1921 Schwartz describes the elimination of Trichinella from food
- 1930 Wuest: French patent on food irradiation
- 1943 MIT becomes active in the field of food preservation for the U.S. Army
- 1951 U.S. Atomic Energy Commission begins to co-ordinate national research activities
- 1958 World first commercial food irradiation (spices) at Stuttgart, Germany
- 1970 Establishment of the International Food Irradiation Project (IFIP), head quarters at the Federal Research Centre for Food Preservation, Karlsruhe, Germany
- 1980 FAOFãoFão is a town in Esposende Municipality in Portugal....
/IAEA/WHOWhoWho may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...
Joint Expert Committee on Food Irradiation recommends the clearance generally up to 10 kGy "overall average dose" - 1981/1983 End of IFIP after reaching its goals
- 1983 Codex AlimentariusCodex AlimentariusThe Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
General Standard for Irradiated Foods: any food at a maximum "overall average dose" of 10 kGy - 1984 International Consultative Group on Food Irradiation (ICGFI) becomes the successor of IFIP
- 1997 FAO/IAEA/WHO Joint Study Group on High-Dose Irradiation recommends to lift any upper dose limit
- 2003 Codex AlimentariusCodex AlimentariusThe Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
General Standard for Irradiated Foods: no longer any upper dose limit - 2004 ICGFI ends
Electron irradiation
Electron irradiation uses electrons accelerated in an electric field to a velocity close to the speed of light. Electrons are particulate radiation and, hence, have cross section many times larger than photons, so that they do not penetrate the product beyond a few inches, depending on product density. Electron facilities rely on substantial concrete shields to protect workers and the environment from radiation exposure.Gamma irradiation
Gamma radiation is radiation of photonPhoton
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
s in the gamma part of the electromagnetic spectrum
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
. The radiation is obtained through the use of radioisotopes, generally cobalt-60
Cobalt-60
Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...
or, in theory, caesium-137
Caesium-137
Caesium-137 is a radioactive isotope of caesium which is formed as a fission product by nuclear fission.It has a half-life of about 30.17 years, and decays by beta emission to a metastable nuclear isomer of barium-137: barium-137m . Caesium-137 is a radioactive isotope of caesium which is formed...
. Cobalt-60 is bred from cobalt-59 using neutron irradiation in specifically designed nuclear reactors. Caesium-137 is recovered during the processing of spent nuclear fuel
Spent nuclear fuel
Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor...
. Because this technology – except for military applications – is not commercially available, insufficient quantities of it are available on the global isotope markets for use in large scale, commercial irradiators. Presently, caesium-137 is used only in small hospital units to treat blood before transfusion to prevent Graft-versus-host disease
Graft-versus-host disease
Graft-versus-host disease is a common complication after a stem cell transplant or bone marrow transplant from another person . Immune cells in the donated marrow or stem cells recognize the recipient as "foreign". The transplanted immune cells then attack the host's body cells...
.
Food irradiation using cobalt-60 is the preferred method by most processors, because the deeper penetration enables administering treatment to entire industrial pallets or totes, reducing the need for material handling. A pallet or tote is typically exposed for several minutes to hours depending on dose. Radioactive material must be monitored and carefully stored to shield workers and the environment from its gamma rays. During operation this is achieved by substantial concrete shields. With most designs the radioisotope can be lowered into a water-filled source storage pool to allow maintenance personnel to enter the radiation shield. In this mode the water in the pool absorbs the radiation. Other uncommonly used designs feature dry storage by providing movable shields that reduce radiation levels in areas of the irradiation chamber.
One variant of gamma irradiators keeps the cobalt-60 under water at all times and lowers the product to be irradiated under water in hermetic bells. No further shielding is required for such designs.
X-ray irradiation
Similar to gamma radiation, X-rayX-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s are photon radiation of a wide energy spectrum and an alternative to isotope based irradiation systems. X-rays are generated by colliding accelerated electrons with a dense material (target) such as tantalum
Tantalum
Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, the name comes from Tantalus, a character in Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion resistant. It is part of the refractory...
or tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
in a process known as bremsstrahlung
Bremsstrahlung
Bremsstrahlung is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into a photon because energy is conserved. The term is...
-conversion. X-ray irradiators are scalable and have deep penetration comparable to Co-60, with the added benefit that the electronic source stops radiating when switched off. They also permit dose uniformity, but these systems generally have low energetic efficiency during the conversion of electron energy to photon radiation requiring much more electrical energy than other systems. Like most other types of facilities, X-ray systems rely on concrete shields to protect the environment and workers from radiation.
Nominal X-ray energy is usually limited to 5 MeV; the USA has provisions for up to 7.5 MeV, which increases conversion efficiency. Another development is the availability of electron accelerators with extremely high power output, up to 1,000 kW beam. At a conversion efficiency of up to 12%, the X-ray power may reach (including filtering and other losses) 100 kW; This power would be equivalent to a gamma facility with Co-60 of about 6.5 MCi.
Current U.S. market
Some U.S. supermarkets carry irradiated food products ranging from fresh tropical fruit from Hawaii or Florida, dehydrated spices, spinach and ground meat products. Certain supermarkets prefer not to carry irradiated products for reasons of consumer perception.Current EU market
The European Community has the most restrictive regulations: mandatory by EC-directive, one single item 'spices' is permitted presently in all 27 member states; seven members (Belgium, Czech Republic, France, Italy, Netherlands, Poland, United Kingdom) maintain a number of national regulations. This leads to the real situation that nearly no irradiated and clearly labelled food item can be found on the market place. The EU-web-pages give information about the regulatory status and the surveillance on the market place.Other and international markets
There is not much information about irradiated food available to the consumer on the market place; a few more recent surveys do not reveal the full picture. It may be assumed that even international trade exists. For example, the United States holds a number of bilateral agreements with countries exporting tropical fruit which is irradiated to eliminate insect pests and to fulfill the quarantine requirements, but no information on amounts traded in reality is available.General economic aspects
Some foods, particularly fruits and vegetables, are not available for sale on the global market unless treated to prolong shelf life for transportation. This may include radiation processing. This application has not yet been exploited. In contrast, irradiation to eliminate insect pests to fulfill quarantine requirements is gaining commercial significance. This is true for fruits Hawaii exports to the U.S. mainland, and increasingly for imports from subtropical countries to the U.S. under bilateral agreements that allows those less-developed countries to earn income through food exports. As an example, Mexico started to export irradiated guavaGuava
Guavas are plants in the myrtle family genus Psidium , which contains about 100 species of tropical shrubs and small trees. They are native to Mexico, Central America, and northern South America...
to the U.S. in 2008 and mango
Mango
The mango is a fleshy stone fruit belonging to the genus Mangifera, consisting of numerous tropical fruiting trees in the flowering plant family Anacardiaceae. The mango is native to India from where it spread all over the world. It is also the most cultivated fruit of the tropical world. While...
in 2009; and has received approval for citrus, star fruit
Carambola
Carambola, also known as starfruit, is the fruit of Averrhoa carambola, a species of tree native to the Philippines, Indonesia, Malaysia, India, Bangladesh and Sri Lanka. The fruit is a popular food throughout Southeast Asia, the South Pacific and parts of East Asia...
and Manzano chili
Rocoto
Capsicum pubescens is a species of the genus Capsicum , which is found primarily in Central and South America. The name component pubescens means hairy, which refers to the hairy leaves of this pepper. The plants, but especially the fruits, are often referred to as rocoto and locoto...
. Some Asian countries hold bilateral agreements to irradiate exotic fruits for quarantine purposes and export it to the USA.
The cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions, i.e., packaging and stacking requirements, construction costs, financing arrangements, and other variables particular to the situation. Irradiation is a capital-intensive technology requiring a substantial initial investment, ranging from $1 million to $5 million. In the case of large research or contract irradiation facilities, major capital costs include a radiation source (cobalt-60), hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), land (1 to 1.5 acres), radiation shield, and warehouse. Operating costs include salaries (for fixed and variable labor), utilities, maintenance, taxes/insurance, cobalt-60 replenishment, general utilities, and miscellaneous operating costs.
Treatment costs vary as a function of dose and facility usage. Low dose applications such as disinfestation of fruit range between US$0.01/lbs and US$0.08/lbs while higher dose applications can cost as much as US$0.20/lbs.
Consumer protection
Irradiation has not been widely adopted due to an asserted negative public perception, the concerns expressed by some consumer groups and the reluctance of many food producers.Consumer organizations, environmentalist groups, and opponents to food irradiation refer to some studies suggesting that a large part of the public questions the safety of irradiated foods, and will not buy foods that have been irradiated.
On the other hand, other studies indicate the number of consumers concerned about the safety of irradiated food has decreased in the last 10 years and continues to be less than the number of those concerned about pesticide residues, microbiological contamination, and other food related concerns. Such numbers are comparable to those of people with no concern about food additives and preservatives. Consumers, given a choice and access to irradiated products, appear ready to buy it in considerably large numbers.
Globalized food supply
Opponents of food irradiation sometimes state that large-scale irradiation would increase processing, transportation, and handling times for fruits and vegetables thus contributing to a negative ecological balance compared to locally grown foods. There is no global trade in irradiated food, except a small quantity of fruit irradiated to eliminate insect pests and to fulfill the US quarantine requirements.Labeling and terminology issues
Labeling laws differ from country to country. While Codex AlimentariusCodex Alimentarius
The Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
represents the global standard in particular under the WTO-agreement, member states are free to convert those standards into national regulations. With regard to labelling of irradiated food, detailed rules are published at CODEX-STAN – 1 (2005) labelling of prepacked food.
The provisions are that any "first generation" product must be labeled "irradiated" as any product derived directly from an irradiated raw material; for ingredients the provision is that even the last molecule of an irradiated ingredient must be listed with the ingredients even in cases where the unirradiated ingredient does not appear on the label. The RADURA-logo is optional; several countries use a graphical version that differs from the Codex-version.
In the U.S., as in many other countries, irradiated food must be labeled as "Treated with irradiation" or "Treated by radiation" and require the use of the Radura
Radura
The Radura is the international symbol indicating a food product has been irradiated. The Radura is usually green and resembles a plant in circle. The top half of the circle is dashed...
symbol at the point of sale. The meaning of the label is not consistent. The amount of irradiation used can vary and since there are no published standards, the amount of pathogens affected by irradiation can vary as well. In addition, there are no regulations regarding the levels of pathogen reduction that must be achieved. Food that is processed as an ingredient by a restaurant or food processor is exempt from the labeling requirement in the US; other countries follow the Codex Alimentarius provision to label irradiated ingredients down to the last molecule (cf. EU).
FDA is currently proposing a rule that in some cases would allow certain irradiated foods to be marketed without any labeling at all. Under the new rules, only those irradiated foods in which the irradiation causes a material change in the food, or a material change in the consequences that may result from the use of the food, would bear the Radura symbol and the term "irradiated", or a derivative thereof, in conjunction with explicit language describing the change in the food or its conditions of use. In the same rule FDA is proposing to permit a firm to use the terms "electronically pasteurized" or "cold pasteurized" in lieu of "irradiated", provided it notifies the agency that the irradiation process being used meets the criteria specified for use of the term "pasteurized".
Food irradiation is sometimes referred to as "cold pasteurization" or "electronic pasteurization" because ionizing the food does not heat the food to high temperatures during the process, as in heat-pasteurization (at a typical dose of 10 kGy, food that is physically equivalent to water would warm by about 2.5 °C). The treatment of solid food by ionizing radiation can provide an effect similar to heat pasteurization of liquids, such as milk. The use of the term "cold pasteurization" to describe irradiated foods is controversial, because pasteurization and irradiation are fundamentally different processes, although the intended end results can in some cases be similar.
Consumer perception of foods treated with irradiation is more negative than those processed by other means. "People think the product is radioactive," said Harlan Clemmons, president of Sadex, a food irradiation company based in Sioux City, Iowa.
Enforcement of labeling
There are analytical methods available to detect the usage of irradiation on food items in the marketplace.This may be understood as a tool for government authorities to enforce existing labeling standards and to bolster consumer confidence. The European Union is particularly strict in enforcing irradiation labeling requiring its member countries to perform tests on a cross section of food items in the market-place and to report to the European Commission; the results are published annually in the OJ of the European Communities.
United States regulators of food irradiation
- United States Department of AgricultureUnited States Department of AgricultureThe United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
(USDA): Meat and poultry products, fresh fruit. - Nuclear Regulatory CommissionNuclear Regulatory CommissionThe Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
(NRC): Safety of the processing facility. - United States Department of TransportationUnited States Department of TransportationThe United States Department of Transportation is a federal Cabinet department of the United States government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967...
(DOT): Safe transport of the radioactive sources.
Each new food is approved separately with a guideline specifying a maximum dosage; in case of quarantine applications the minimum dose is regulated. Packaging materials containing the food processed by irradiation must also undergo approval.
The Radura logo as regulated by FDA is slightly different from the international version as proposed in Codex Alimentarius.
Safety, security and wholesomeness aspects
Hundreds of animal feeding studies of irradiated food, including multigenerational studies, have been performed since 1950. Endpoints investigated have included subchronic and chronic changes in metabolism, histopathology, and function of most systems; reproductive effects; growth; teratogenicity; and mutagenicity. A large number of studies have been performed; meta-studies have supported the safety of irradiated food.Consumer advocacy groups such as Public Citizen
Public Citizen
Public Citizen is a non-profit, consumer rights advocacy group based in Washington, D.C., United States, with a branch in Austin, Texas. Public Citizen was founded by Ralph Nader in 1971, headed for 26 years by Joan Claybrook, and is now headed by Robert Weissman.-Lobbying Efforts:Public Citizen...
or Food and Water Watch
Food and Water Watch
Food & Water Watch is a Washington, D.C.-based non-governmental organization and consumer rights group which focuses on corporate and government accountability relating to food, water, and fishing. Food and Water Watch employs a four pronged effort focusing on public and policymaker education,...
maintain that the safety of irradiated food is not proven, in particular long-term studies are still lacking, and strongly oppose the use of the technology.
A report of fatal incidences with pet food in Australia led to some rumours and speculation about the safety of irradiated food and a nationwide recall. In the Australian case, sixteen cats were reported to have been euthanized after severe paralysis subsequent to being fed a certain cat food. The company issuing a recall stated that the problem only occurred with Australian pet-food. The company speculated this was due to irradiating the pet-food. The Australian Quarantine Inspection Services (AQIS) (at that time) required the irradiation to a minimum dose of 50 kGy or heating of imported dry food. After the incident, the pet food manufacturer created a compassion fund for pet owners. The cause of the cat illness is not yet clearly understood and is still under investigation and verification. Vitamin A depletion was not confirmed in the affected cats. Researchers from Wisconsin University announcing their conference presentation said in the published abstract: "Here, we show that cats fed an irradiated diet during gestation developed a severe neurologic disease resulting from extensive myelin vacuolation and subsequent demyelination."
Radiation processing of imported cat food has now been banned in Australia. Previously it had been a mandatory requirement for imports including dry and semi-moist food to be irradiated at a minimum dose of 50 kGy or to be heated to a temperature of 100 °C (212 °F) for a minimum of 30 minutes. The AQIS – having jurisdiction on quarantine issues – announced on June 6, 2009 that the alternative of radiation processing for cat food is no longer acceptable and that irradiated dog food needs to be labeled by "Must not be fed to cats". AQIS in its announcement refers to recently published scientific studies and reminds importers of their responsibility to regularly check whether new scientific results could have any implication for their products. Australia does not permit food irradiation, generally; at present only dog feed may be irradiated upon import, but must be labelled 'do not feed to cats'. Dr. G. Child has published a report of the clinical signs and outcomes of those cats. The authors point to epidemiological and to toxicological studies that are still underway. It is not yet clear which mechanism and what changes in irradiated pet food cause damages in the white matter of spinal cord and brain.
Criticism and concerns about food irradiation
Concerns have been expressed by public interest groups and public health experts 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 contaminationContamination
Contamination is the presence of a minor and unwanted constituent in material, physical body, natural environment, at a workplace, etc.-Specifics:"Contamination" also has more specific meanings in science:...
in the first place.
Concerns and objections include the possibility that food irradiation might do any of the following:
- Mask spoiled food
- Discourage strict adherence to good manufacturing practices
- Preferentially kill "good" bacteria and encourage growth of "bad" bacteria
- Devitalize and denature irradiated food
- Impair flavor
- Not destroy bacterial toxins already present
- Cause chemical changes that are harmful to the consumer
- Be unnecessary in today's food system
Processors of irradiated food are subject to all existing regulations, inspections, and potential penalties regarding plant safety and sanitation; including fines, recalls, and criminal prosecutions. But critics of the practice claim that a lack of regulatory oversight (such as regular food processing plant inspections) necessitates irradiation.
While food irradiation can in some cases maintain the quality (i.e. general appearance and "inner" quality) of certain perishable food for a longer period of time, it cannot undo spoilage that occurred prior to irradiation. Irradiation cannot successfully be used to mask quality issues other than pathogens. As with heat pasteurization (for example, milk), processing by ionizing radiation can contribute to eliminate pathogen risks from solid food (example meat or lettuce). For comparison, milk heat pasteurization is not being alleged to be a method "to cover up poor food quality"; consequently, food irradiation should not be accused to serve such criminal purposes. Under a HACCP-concept (Hazard Analysis and Critical Control Point) radiation processing can serve and contribute as an ultimate critical control point before the food reaches the consumer.
Opponents of food irradiation and consumer activists argue that the final proof is missing that irradiated food is "safe" (i.e. not unwholesome) and that the lack of long-term studies should be a further reason not to permit food irradiation. Opponents also refer to a number of scientific publications reporting significant negative effects of irradiated food, for example
- PolyploidyPolyploidyPolyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
in malnourished Indian children - Increase of aflatoxinAflatoxinAflatoxins are naturally occurring mycotoxins that are produced by many species of Aspergillus, a fungus, the most notable ones being Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are toxic and among the most carcinogenic substances known...
production by irradiated microorganisms - Vitamin deficiencies at extremely high doses to the complete diet
- Non-vitamin effects at higher doses (free radicals?)
- Change in chronaxieChronaxieIn the mathematical description of the functioning of the nervous system, the chronaxie is the minimum time over which an electric current, double the strength of the rheobase, needs to be applied, in order to stimulate a muscle fiber or nerve cell.The terms "chronaxie" and "rheobase" were coined...
in rats
However, those experiments could be either not verified in later experiments, could not be clearly attributed to the radiation effect, or could be attributed to an inappropriate design of the experiment etc.
Worker safety and impact on the environment
The safety of irradiation facilities is regulated by the United Nations International Atomic Energy AgencyInternational Atomic Energy Agency
The International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...
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.
Care must be taken not to expose the operators and the environment to radiation or radioactive contamination. 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. "Ordinary" occupational safety regulations also apply to radiation processing facilities; the radiation aspects are typically excluded and supervised by special authorities.
An incident in Decatur, Georgia
Decatur, Georgia
Decatur is a city in, and county seat of, DeKalb County, Georgia, United States. With a population of 19,335 in the 2010 census, the city is sometimes assumed to be larger since multiple zip codes in unincorporated DeKalb County bear the Decatur name...
where water soluble caesium-137 leaked into the source storage pool requiring NRC
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
intervention has led to near elimination of this radioisotope; it has been replaced by the more costly, non-water soluble cobalt-60.
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, and, hence, excluding the risk to workers and the environment.
Alternatives
Other methods to reduce several pathogens in food include heat-pasteurizationPasteurization
Pasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food...
, ultra-high temperature processing, UV irradiation
Ultraviolet germicidal irradiation
Ultraviolet germicidal irradiation is a sterilization method that uses ultraviolet light at sufficiently short wavelength to kill microorganisms. It is used in a variety of applications, such as food, air and water purification. UV has been a known mutagen at the cellular level for more than...
, ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...
, Pascalization
Pascalization
Pascalization, bridgmanization, or high pressure processing , is a method of preserving and sterilizing food, in which a product is processed under very high pressure, leading to the inactivation of certain microorganisms and enzymes in the food...
, Thermization
Thermization
Thermization, also spelled thermisation, is a method of sterilizing raw milk with heat. The process is not used on other food products, and is similar to pasteurization but uses lower temperatures, allowing the milk product to retain more of its original taste. In Europe, there is a distinction...
or fumigation with ethylene oxide
Ethylene oxide
Ethylene oxide, also called oxirane, is the organic compound with the formula . It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape . This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered...
.
For quarantine purposes, insect pests can also be eliminated by fumigation with methyl bromide or aluminium phosphine, vapour heat, forced hot air, hot water dipping, or cold treatment.
Other methods to extend shelf life of food items include modified atmosphere packaging, carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
, dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
, vacuum packaging, freezing
Freezing
Freezing or solidification is a phase change in which a liquid turns into a solid when its temperature is lowered below its freezing point. The reverse process is melting....
and flash freezing
Flash freezing
Flash freezing refers to the process in various industries whereby objects are quickly frozen by subjecting them to cryogenic temperatures....
as well as chemical additives.
Opponents of food irradiation and consumer activists (cf. Public Citizen) maintain that the best alternative to food irradiation to reduce pathogens is in good agricultural practices. 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.
Proponents of food irradiation have said that practices of organic farming can only reduce the extent of the microorganism load. They assert that residual flora including pathogen germs always persist, and that processing by ionizing radiation could be the ultimate measure (as a CCP under a HACCP-concept) to practically eliminate such risks.
See also
- Deinococcus radioduransDeinococcus radioduransDeinococcus radiodurans is an extremophilic bacterium, one of the most radioresistant organisms known. It can survive cold, dehydration, vacuum, and acid, and is therefore known as a polyextremophile and has been listed as the world's toughest bacterium in The Guinness Book Of World Records.-Name...
- Food labeling regulations (disambiguation)
- Food and cooking hygiene
- Irradiated mailIrradiated mailIrradiated mail is mail that has been deliberately exposed to radiation, typically in an effort to disinfect it. The most notable instance of mail irradiation occurred in response to the 2001 anthrax attacks; the level of radiation chosen to kill anthrax spores was so high that it often changed the...
- Local foodLocal foodLocal food or the local food movement is a "collaborative effort to build more locally based, self-reliant food economies - one in which sustainable food production, processing, distribution, and consumption is integrated to enhance the economic, environmental and social health of a particular...
Further reading
- World Health OrganizationWorld Health OrganizationThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
publications:- Food irradiation – A technique for preserving and improving the safety of Food, WHO, Geneva, 1991 (revised)
- Wholesomeness of irradiated food, WHO, Geneva, Technical Report Series No. 659, 1981
- Safety and nutritional adequacy of irradiated food, WHO, Geneva, 1994
- High-dose irradiation: Wholesomeness of food irradiated with doses above 10 kGy, WHO, Geneva, 1999, Technical Report Series No. 890
- WHO Statement on 2-Dodecylcyclobutanone and Related Compounds, 2003
- Facts about Food Irradiation, A series of Fact Sheets from the International Consultative Group on Food Irradiation (ICGFI), 1999, IAEA, Vienna, Austria
- Diehl, J.F., Safety of irradiated foods, Marcel Dekker, N.Y., 1995 (2. ed.)
- Satin, M., Food irradiation, Technomic, Lancaster, 1996 (2. ed.)
- Urbain, W.M., Food irradiation, Academic Press, Orlando, 1986
- Molins, R. (ed.), Food irradiation – Principles and applications, Wiley Interscience, N.Y., 2001
- Sommers, C.H. and Fan, X. (eds.), Food Irradiation Research and Technology, Blackwell Publishing, Ames, IA, 2006
- Hauter, W. and Worth, M., Zapped! Irradiation and the Death of Food, Food & Water Watch Press, Washington, DC, 2008.
- "The food that would last forever : understanding the dangers of food irradiation" by Gary Gibbs, Garden City Park, N.Y. : Avery Pub. Group, c1993
- anon., Food Irradiation: Available Research Indicates That Benefits Outweigh Risks, RCED-00-217, August 24, 2000, Government Accountability Office, United States General Accounting Office, Resources, Community, and Economic Development Division, Washington, D.C. 20548 "Food Irradiation"
- Farkas, J. and Mohácsi-Farkas, C., History and future of food irradiation, Food Sci. Technol. 22(2011),121-128
External links
- Codex AlimentariusCodex AlimentariusThe Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines and other recommendations relating to foods, food production and food safety. Its name derives from the Codex Alimentarius Austriacus...
- Food Irradiation Processing Alliance FIPA represents the irradiation service industry, manufacturers of food irradiators and suppliers of cobalt-60 sources.
- Food & Water Watch – food irradiation page
- U.S. Food Irradiation FAQ, Food and Water WatchFood and Water WatchFood & Water Watch is a Washington, D.C.-based non-governmental organization and consumer rights group which focuses on corporate and government accountability relating to food, water, and fishing. Food and Water Watch employs a four pronged effort focusing on public and policymaker education,...
- Remarks by Mark Worth, Public Citizen, to the FDA, Jan. 12, 2005
- Irradiation of Food and Food Packaging, Center for Food Safety and Applied NutritionCenter for Food Safety and Applied NutritionThe Center for Food Safety and Applied Nutrition is the branch of the United States Food and Drug Administration that regulates food, dietary supplements, and cosmetics .-Area of regulation:...
(US Government) - Irradiation Fact Sheet, Center for Food SafetyCenter for Food SafetyThe Center for Food Safety is a U.S. non-profit organization, based in Washington, D.C., that also maintains an office in San Francisco, CA...
(US non-profit organisation) - Facts about Food Irradiation, a series of 14 fact sheets, International Consultative Group on Food Irradiation, International Atomic Energy AgencyInternational Atomic Energy AgencyThe International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...
, Vienna, 1991 - Bibliography on Food Irradiation, Federal Research Centre for Nutrition and Food, Karlsruhe, GermanyKarlsruheThe City of Karlsruhe is a city in the southwest of Germany, in the state of Baden-Württemberg, located near the French-German border.Karlsruhe was founded in 1715 as Karlsruhe Palace, when Germany was a series of principalities and city states...
- Should we irradiate fruit and vegetables? Dateline NBCDateline NBCDateline NBC, or Dateline, is a U.S. weekly television newsmagazine broadcast by NBC. It previously was NBC's flagship news magazine, but now focuses on true crime stories. It airs Friday at 9 p.m. EST and after football season on Sunday at 7 p.m. EST.-History:Dateline is historically notable for...
investigation - Irradiation FAQ provided by BENEBION of Mexico
- anon. What's wrong with food irradiation, revised Feb. 2001, Organic Consumers Association, USA
- Comment by Dr. Henry Delincée on an affidavit misrepresenting the conclusions of his studies on unique radiolytical byproducts
- The Basics on the Foodfight Over Irradiation | health.usnews.com