Facts

food
about
irradiation

A series of Fact Sheets from the International Consultative Group on Food Irradiation
ICGFI is an international group of experts designated
by Governments to evaluate and advise on global
activities of food irradiation
For further information contact:

Head
Food and Environmental Protection Section
Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture
International Atomic Energy Agency
Wagramer Strasse 5, P.O.Box 100, A-1400 Vienna, Austria
Telex:112645, Cable:INATOM VIENNA, Facsimile: (+43 1) 26007
Telephone:(+43 1) 2600-21640, E-Mail: Official.Mail@iaea.org
Also visit ICGFI-Web Page (http://www.iaea.org/icgfi/)

Funds for graphic design of this document for the International

Consultative Group on Food Irradiation (ICGFI), Vienna, Austria,
provided by
PURIDEC Irradiation Technology,
6 Chiltern Court, Asheridge Road, CHESHAM, Buckinghamshire,
England HP5 2 PX

Design: WorldLinks/Vienna
Illustrations: Camilo Melgar

© 1999 International Consultative Group on Food Irradiation

 Facts
food
about
irradiation
A series of Fact Sheets from the
International Consultative Group
on Food Irradiation (ICGFI)
Contents

Status and Trends ..........................................................................3

Scientific and Technical Terms ......................................................7

Benefits of Food Irradiation ..........................................................9

Food Irradiation Facilities ............................................................17

Safety of Irradiated Food ............................................................22

Nutritional Quality of Irradiated Foods ......................................28

Packaging of Irradiated Foods ....................................................30

Food Irradiation Costs ..................................................................32

Trade in Irradiated Foods ............................................................34

Detection Methods for Irradiated Food ......................................36

Irradiated Foods and the Consumer ............................................38

Further Reading ..........................................................................45

 Fo r e w o r d

The safety and benefits of foods processed by ionizing radiation are well documented. In an
effort to provide governments with scientifically accurate information on issues of general interest
to the public, the International Consultative Group on Food Irradiation (ICGFI), which was
established under the aegis of the Food and Agriculture Organization of the United Nations (FAO),
the World Health Organization (WHO), and the International Atomic Energy Agency (IAEA), decided
at its 7th Annual Meeting in Rome, Italy, in October 1990, to issue a series of “Fact Sheets” on
the subject. The Fact Sheets were first issued by the ICGFI Secretariat (Joint FAO/IAEA Division of
Nuclear Techniques in Food and Agriculture, Vienna, Austria) in May 1991.

ICGFI, an inter-governmental body with a membership of 46 governments in 1999, has as

one of its mandates the function to provide information to Member States of the FAO,
WHO, and IAEA and to the three organizations themselves on the safe and proper
use of food irradiation technology. Since publication of the Fact Sheets in 1991, many
developments have taken place in the field of food irradiation. This booklet reports
the latest developments in the use of food irradiation. The revised Fact Sheets included
here cover issues relating to: status and trends; scientific and technical terms; benefits of food
irradiation; food irradiation facilities; safety of food irradiation; nutritional quality of irradiated
foods; packaging of irradiated foods; food irradiation costs; trade in irradiated foods; detection
methods for irradiated foods; and irradiated foods and the consumer.

The ICGFI Secretariat would like to acknowledge the contribution of Dr. Eileen Stewart,
Department of Food Science, Queen’s University of Belfast, Belfast, Northern Ireland in revising
this brochure and of Dr. Paul Thomas, former Head, Food Technology Division, Bhabha Atomic
Research Centre, Trombay, India, in finalizing it. It also would like to thank Dr. Christine M. Bruhn,
Director, Centre for Consumer Science, University of California, Davis, California and Mr. D.D. Derr,
food safety consultant, former Deputy Director of USDA/FSIS, Glen Burnie, Maryland, for reviewing
this brochure.

Facts about food irradiation / 1

 S t at u s a n d Tr e n d s

Food irradiation is the treatment of food by a certain type foods, ranging from spices to grains to deboned chicken
of energy. The process involves exposing the food, either meat, to beef, to fruits and vegetables. As of August 1999,
packaged or in bulk, to carefully controlled amounts of over 30 countries are irradiating food for commercial
ionizing radiation for a specific time to achieve certain purposes. There are approximately 60 irradiation facilities
desirable objectives as will be detailed later in the text. being used for this purpose with more under construction
The process cannot increase the normal radioactivity level or at the planning stage.
of the food, regardless of how long the food is exposed to
the radiation, or how much of an energy “dose” is Decisions in these and other countries to irradiate food
absorbed. It can prevent the division of microorganisms have been influenced by the adoption, in 1983, of a
which cause food spoilage, such as bacteria and moulds, worldwide standard covering irradiated foods. The
by changing their molecular structure. It can also slow down standard was adopted by the Codex
ripening or maturation of certain fruits and vegetables by Alimentarius Commission, a joint
modifying/altering the physiological processes of the plant body of the Food and Agriculture
tissues. Organization of the United Nations
(FAO) and the World Health Orga-
nization (WHO), responsible for
Who is interested in the process? issuing food standards to protect
consumer health and facilitate fair practice in
Alongside traditional methods of processing and pre- food trade, representing more than 150 governments. The
serving food, the technology of food irradiation is gaining Codex General Standard for food irradiation was based on
more and more attention around the world. Although the findings of a Joint Expert Committee on Food Irradiation
regarded as a new technology by some individuals, (JECFI) convened by the FAO, WHO, and the International
research on food irradiation dates back to the turn of the Atomic Energy Agency (IAEA). The JECFI has evaluated
century with the first USA and British patents being issued available data in 1964, 1969, 1976, and 1980. In 1980,
in 1905 for the use of ionizing radiation to kill bacteria in it concluded that “the irradiation of any food commodity”
food. Today, health and safety authorities in over 40 up to an overall average dose of 10 kGy “presents no
countries have approved irradiation of over 60 different toxicological hazard” and requires no further testing. It

Facts about food irradiation / 3

 š
The use of irradiation alone as a
stated that irradiation up to 10 kGy alternative to protect food against insect
preservation technique will not
“introduces no special nutritional or damage and as a quarantine treatment
microbiological problems” in foods. In solve all the problems of post- of fresh produce.
September 1997 a Study Group was harvest food losses, but it can play
jointly convened by the WHO, FAO and an important role in cutting losses The FAO has estimated that worldwide
IAEA to evaluate the wholesomeness about 25% of all food production is lost
and reducing the dependence on
of food irradiated with doses above to insects, bacteria and rodents after
10 kGy. This Study Group concluded chemical pesticides. harvesting. The use of irradiation alone
that there is no scientific basis for š as a preservation technique will not
limiting absorbed doses to the upper solve all the problems of post-harvest
level of 10 kGy as currently recommended by the Codex food losses, but it can play an important role in cutting
Alimentarius Commission. Food irradiation technology is losses and reducing the dependence on chemical pesticides.
safe to such a degree that as long as the sensory qualities Many countries lose vast amounts of grain because of insect
of food are retained and harmful microorganisms are infestation and moulds. For roots and tubers, sprouting is
destroyed, the actual amount of ionizing radiation applied the major cause of losses. Several countries, including
is of secondary consideration. Bangladesh, Chile, China, Hungary, Japan, Republic of Korea
and Thailand are irradiating one or more food products
(grains, potatoes, spices, dried fish, onions, garlic, etc.) to
Why are countries interested? control food losses on a commercial basis.

Interest in the irradiation process is increasing because of Foodborne diseases pose a widespread threat to human
persistently high food losses from infestation, contamination, health and they are an important cause of reduced economic
and spoilage; mounting concerns over food-borne diseases; productivity even in advanced countries which have modern
and growing international trade in food products that must food processing and distribution systems. Although the
meet strict import standards of quality and quarantine, all amount of foodborne disease caused by pathogenic bacteria
areas in which food irradiation has demonstrated practical in the United States is not known with accuracy, it was
benefits when integrated within an established system for estimated in 1994 by a task force of the Council for
the safe handling and distribution of food. In addition, with Agricultural Science and Technology (CAST) that the number
increasingly restricted regulations or complete prohibition of cases likely range from 6.5 million to 33 million annually
on the use of a number of chemical fumigants for insect and that deaths may be as high as 9,000 annually. The
and microbial control in food, irradiation is an effective United States Department of Agriculture’s (USDA) Economic

4 / Facts about food irradiation

Research Service estimates that diseases caused by E. coli poultry meat is carried out industrially in France. Spices are
O157:H7 due to consumption of insufficiently cooked ground being irradiated (instead of being fumigated) in many
beef result in US $200 million to $440 million in annual countries including Argentina, Belgium, Brazil, Canada, China,
medical costs and productivity losses. In developing Denmark, Finland, France, Hungary, Indonesia, Israel, Mexico,
countries, diseases caused by parasites such as Taenia the Netherlands, Norway, Republic of Korea, South Africa, the
solium and Trichinella spiralis constitute a major problem, United Kingdom and the USA. The volume of irradiated spices
and together with bacterial foodborne diseases, account for and dried vegetable seasonings globally has increased
hundreds of millions of cases per year. significantly in recent years to over 60,000 tonnes in 1997.

The relatively low doses of radiation needed to destroy certain Trade in food products is a major factor in regional and
bacteria in food can be useful in controlling foodborne international commerce, and markets are growing. The
disease. Considerable amounts of frozen seafoods and frog inability of countries to satisfy each other’s quarantine and
legs, as well as dry food ingredients, are irradiated for this public health regulations is a major barrier to trade. For
purpose in Belgium, France and the Netherlands. Electron example, not all countries allow importation of chemically-
beam irradiation of blocks of frozen mechanically deboned, treated fruit. Moreover, major importing countries, including

Estimated quantities of irradiated spices and dried vegetable seasonings

China
80 Others
Quantity (1,000 metric tonnes)

70 Belgium
USA
60
Netherlands
50 Canada
40 South Africa
France
30
Mexico
20 Republic of Korea
10
0
1987 1991 1994 1998

Facts about food irradiation / 5

 from export. Radiation processing offers these countries an
alternative to fumigation and some other treatments.

How much food is being commercially

irradiated?

Each year a few hundred thousand tonnes of food

products and ingredients are irradiated worldwide. This
amount is small in comparison to the total volumes of
processed foods and not many of these irradiated food
products enter international commerce.

Irradiation can expand widely trade in fresh fruits and vegetables One factor influencing the speed with which food irradiation
is being adopted is public understanding and acceptance of
the USA and Japan, have banned the use of and the import the process. Contrary to earlier estimates it has been
of produce treated with certain fumigants identified as demonstrated that when irradiated foods are available,
health hazards. During 1996, the United States Department consumers have purchased them because of their satis-
of Agriculture (USDA) issued a new policy to allow faction with product quality and safety. It is normal to seek
importation of fresh fruits and vegetables treated by reassurance as to the safety and effectiveness of any new
radiation against fruit flies. The problem is most acute for process or technology. Therefore, it is hoped that this
developing countries whose economies are still largely revised publication will help address concerns and correct
based on food and agricultural production and the revenues myths about food irradiation.

6 / Facts about food irradiation

 S c i e n t i f i c a n d Te c h n i c a l Te r m s

The type of radiation used in processing materials is limited cesium-137; X-ray machines having a maximum energy of
to radiations from high energy gamma rays, X-rays and five million electron volts (MeV) (an electron volt is the
accelerated electrons. These radiations are also referred to amount of energy gained by an electron when it is
as ionizing radiations because their energy is high enough accelerated by a potential of one volt in a vacuum); or
to dislodge electrons from atoms and molecules and to electron accelerators having a maximum energy of 10 MeV.
convert them to electrically-charged particles called ions. Energies from these radiation sources are too low to induce
radioactivity in any material, including food.
Gamma rays and X-rays, like radiowaves, microwaves,
ultraviolet and visible light rays, form part of the electro- The radionuclide used almost exclusively
magnetic spectrum and occur in the short-wavelength, for the irradiation of food by
high-energy region of the spectrum and have the greatest gamma rays is cobalt-60. It is
penetrating power. They have the same properties and produced by neutron bombard-
effects on materials, their origin being the main difference ment in a nuclear reactor of the
between them. X-rays with varying energies are generated metal cobalt-59, then doubly en-
by machines. Gamma rays with specific energies come from capsulated in stainless steel “pencils”
the spontaneous disintegration of radionuclides. to prevent any leakage during its use in an
irradiator. Cobalt-60 has a half-life of 5.3 years, the
Naturally occurring and man-made radionuclides, also called gamma rays produced are highly penetrating and can be
radioactive isotopes or radioisotopes, emit radiation as they used to treat full boxes of fresh or frozen food. Cesium-137
spontaneously revert to a stable state. The time taken by a is the only other gamma-emitting radionuclide suitable for
radionuclide to decay to half the level of radioactivity originally industrial processing of materials. It can be obtained by
present is known as its half-life, and is specific for each reprocessing spent, or used, nuclear fuel elements and has
radionuclide of a particular element. The becquerel (Bq) is the a half-life of 30 years. However, there is no supply of
unit of radioactivity and equals one disintegration per second. commercial quantities of cesium-137. Cobalt-60 has
therefore become the choice for gamma radiation source;
Only certain radiation sources can be used in food over 80% of the cobalt-60 available in the world market is
irradiation. These are the radionuclides cobalt-60 or produced in Canada. Other producers are the Russian

Facts about food irradiation / 7

 Cosmic Gamma Ultraviolet Visual Infrared
Rays Rays X-Rays (Sun Rays) Light (Heat Waves) Microwaves Radio Waves AC Power

High Frequency Low Frequency

(Short Wavelengths) (Long Wavelengths)

Electromagnetic spectrum

Federation, the People’s Republic of China, India and WHO showed that food treated according to good manu-
South Africa. facturing practices (GMPs) at any dose above 10 kGy is also
safe for consumption, making irradiation parallel to heat
High energy electron beams can be produced from machines treatment of food. In terms of energy relationships, one gray
capable of accelerating electrons to near the speed of light equals one joule of energy absorbed per kilogram of food
by means of a linear accelerator. Since electrons cannot being irradiated. The maximum dose of 10 kGy recommended
penetrate very far into food, compared with gamma radiation by the Codex General Standard for Irradiated Foods is
or X-rays, they can be used only for treatment of thin equivalent to the heat energy required to increase the
packages of food and free flowing or falling grains. X-rays of temperature of water by 2.4°C. Irradiation is often referred to
various energies are produced when a beam of accelerated as a “cold pasteurization” process as it can accomplish the
electrons bombards a metallic target. Although X-rays have same objective as thermal pasteurization of liquid foods, for
good penetrability into food, the efficiency of conversion from example milk, without any substantial increase in product
electrons to X-rays is generally less than 10%, and this has temperature.
hindered the use of this type of radiation source so far.
Table Units of Radiation Dose and Radioactivity
Radiation dose is the quantity of radiation energy absorbed Absorbed dose Radioactivity
by the food as it passes through the radiation field during
processing. It is measured using a unit called the Gray (Gy). Unit gray (Gy) becquerel (Bq)
In early work the unit was the rad (1 Gy = 100 rads; 1 kGy = Definition 1 Gy = 1 J/kg 1 Bq = 1 disintegration/sec
1000 Gy). International health and safety authorities have Former unit rad curie (Ci)
Conversion 1 rad = 0.01 Gy 1 Ci = 3.7 X 1010Bq = 37 GBq
endorsed the safety of irradiation for all foods up to a dose
1 krad = 10 Gy 1 kCi = 37 TBq
level of 10,000 Gy (10 kGy). Recent evaluation of an 1 Mrad = 10 kGy 1 mCi = 37 PBq
international expert study group appointed by FAO, IAEA and

8 / Facts about food irradiation

 B e n e f i t s o f fo o d i r ra d i at i o n

What are the benefits which can be gained or semi-solid foods, especially those of animal origin,
from irradiating food? through inactivation of foodborne pathogens. This
application is comparable to thermal pasteurization of
Finding ways to prevent the deterioration of food and liquid foods, for example milk, which is effective and
control infection by microorganisms has been a major pre- widely applied but is unsuitable for foods such as poultry,
occupation of man over the centuries. Controls such as meat and seafood that are to be marketed in raw form.
refrigeration or pasteurization are now commonplace, and it
is expected that one day the technique of food irradiation Reduction of pathogenic microorganisms
will also be widely used. Food irradiation can offer a wide
range of benefits to food industry and the consumer. From The incidence of foodborne disease
a practical point of view, there are three general application arising from the consumption of food
and dose categories that are referred to when foods are contaminated with pathogenic micro-
treated with ionizing radiation: organisms is increasing, and there is a
heightened public awareness of the
Low-dose irradiation – up to » 1 kGy (sprout inhibition; delay health threat posed by pathogens in
of ripening; insect disinfestation; parasite inactivation). or on food. Among these, Escherichia
coli O157:H7, Salmonella, Campylobacter jejuni, Listeria
Medium-dose irradiation – 1 to 10 kGy (reduction in numbers monocytogenes, and Vibrio are of primary concern from a
of spoilage microorganisms; reduction in numbers or public health standpoint because of the severity of the
elimination of non-spore-forming pathogens, i.e. disease illnesses and/or because of the higher number of outbreaks
causing microorganisms). and individual cases of foodborne illness associated with
these pathogens. Of these food poisoning bacteria,
High-dose irradiation – above 10 kGy (reduction in numbers Salmonella and C. jejuni are usually associated with poultry.
of microorganisms to the point of sterility). E. coli O157:H7 has also been linked to major foodborne
disease outbreaks through many sources including meat and
Perhaps the most important application of this method of dairy products in the United Kingdom, hamburger meat, apple
food preservation is to ensure the hygienic quality of solid juice and water in the USA, and vegetables in Japan. Listeria

Facts about food irradiation / 9

 – following his research on spoilage in wine, Louis Pasteur
recommended a level of heat treatment that was sufficient to
inactivate spoilage microorganisms but not high enough to
destroy the quality or character of the products processed.
He therefore determined the minimum processing required to
attain the desired objective without impairing the product’s
overall acceptability.

With fresh poultry carcasses, irradiation up to a dose of 2.5

kGy will virtually eliminate Salmonella and Campylobacter
under proper production conditions. The same dose of
irradiation destroys E. coli O157:H7, a highly virulent bacteria
Irradiation is a unique method to ensure microbial safety in raw foods. which can lead to illness and death, and which is estimated
to cause 20,000 infections and 250 deaths in the USA
monocytogenes has been associated with dairy products, annually. Irradiation is currently the only known method to
processed meats and other foods having a relatively long inactivate these pathogens in raw and frozen food.
shelf-life under refrigeration. Vibrio spp. in turn have been the
causitive agents in world cholera pandemics and of many Frog legs can be heavily contaminated by Salmonella and
outbreaks of disease caused by consumption of raw mollusks. other pathogens, and irradiation provides an effective means
of decontamination. French importers have routinely
Adherence to good manufacturing practice (GMP) is obviously irradiated this product for a number of years, and irradiated
essential but this alone may not be sufficient to reduce the frozen frog legs can be purchased in most French food
number of food poisoning outbreaks. Pathogens such as markets. Eggs and egg products are often contaminated with
those mentioned previously are sensitive to low levels of Salmonella and have been the subject of many food
ionising radiation. As the irradiation dose increases more irradiation studies. Early work in the United Kingdom showed
microorganisms are affected but a higher dose, although not that frozen egg and dried egg could be irradiated at doses of
creating any harmful products, may simultaneously introduce up to 5 kGy without quality loss and that this dose provided
changes in sensory qualities and therefore a balance must be sufficient hygienic protection. More recent work suggests 2
attained between the optimum dose required to achieve a kGy as the most suitable dose for inactivation of
desired objective and that which will minimise any sensory Salmonella in egg powder; at the same time preserving
changes. This is also the case for thermal-pasteurization the sensory and technological properties.

10 / Facts about food irradiation

Seafood, especially shellfish, is often contaminated with
pathogenic organisms such as Salmonella, Vibrio parahaemo-
lyticus, and Shigella. Consumption of raw and inadequately
cooked shellfish is considered to present unacceptable risk
factors. Nevertheless, many people do eat raw shellfish such
as oysters and clams. In frozen shrimp, reduction of pathogens
to a safe level requires a dose of about 3 kGy for inactivating
Vibrio spp., Salmonella spp. and Aeromonas hydrophila.

It is well known in some countries that fresh pork meat must Irradiation is an effective residue free method for microbial decontamination
be cooked thoroughly because it may contain Trichinella of spices

spiralis, a parasite which may cause illness and death. The contaminating microorganisms. However, the use of ethylene
larvae of this parasite can be rendered non-infective by oxide was prohibited by an European Union (EU) directive in
irradiation with a minimum dose of 0.3 kGy. Pork treated in 1991 and has been banned in a number of other countries
this manner is known as “trichina-safe”. Another pork because it is a carcinogen. Irradiation has since emerged as a
parasite Toxoplasma gondii can also be inactivated with a viable alternative and its use results in cleaner, better quality
minimum dose of 0.5 kGy. herbs and spices compared to those fumigated with ethylene
oxide. Irradiation of spices on a commercial scale is practised
in over 20 countries and global production has increased
Decontamination significantly from about 5,000 tonnes in 1990 to over 60,000
tonnes in 1997. In the USA alone over 30,000 tonnes of spices,
Spices, herbs and vegetable seasonings are valued for their herbs and dry ingredients were irradiated in 1997 as compared
distinctive flavours, colours and aromas. However, they are to 4,500 tonnes in 1993.
often heavily contaminated with microorganisms because of
the environmental and processing conditions under which they
are produced. Therefore, before they can be safely in- Extension of shelf-life
corporated into other food products, the microbial load should
be reduced. Because heat treatment can cause significant loss The shelf-life of many fruits and vegetables, meat, poultry,
of flavour and aroma, a “cold process”, such as irradiation, is fish and seafood can be considerably prolonged by
ideal. Until recently, most spices and herbs were fumigated, treatment with combinations of low-dose irradiation and
usually with sterilizing gases such as ethylene oxide to destroy refrigeration that do not alter flavour or texture. Many

Facts about food irradiation / 11

 initial quality of the fresh food, which should be as good as
possible. Irradiation of mushrooms at 2 to 3 kGy inhibits
cap opening and stem elongation. Shelf-life extension can
be increased at least two-fold by irradiation and subsequent
storage at 10°C, and even longer when stored at a lower
temperature compared with non-irradiated mushrooms.

Not all fruits and vegetables are suitable for irradiation

because undesirable changes in colour or texture, or both,
limit their acceptability. Also, different varieties of the
Shelf-life of strawberries can be extended by irradiation same fruit or vegetable may respond differently to
irradiation. The time of harvest and the physiological state
spoilage microorganisms, such as Pseudomonas spp., are also affects the response of fruits and vegetables to
relatively sensitive to irradiation. For example, a dose of 2.5 irradiation. For example, if strawberries are irradiated
kGy applied to fresh poultry carcasses processed according before they are ripe, the red colour does not develop
to good manufacturing practices (GMPs) will be enough to satisfactorily. For delaying ripening in fruits it is important
eliminate Salmonella, and will also kill many, but not all, to irradiate them before ripening starts.
spoilage bacteria. This will double meat shelf-life, provided
it is kept below 5°C. At high doses of irradiation (>25 kGy), foods which are pre-
heated to inactivate enzymes can be commercially sterilized
Extension of the very short shelf-life of many commercially such as occurs in canning. The sterilized products can be
important plant commodities is highly desirable, and in stored at room temperature almost indefinitely. Radiation-
some cases, critical. Exposure to a low dose of radiation sterilized foods are given to hospital patients who have
can slow down the ripening of some fruits, control fungal immune system deficiencies and must therefore have a sterile
rot in some others and maturation in certain vegetables, diet. Irradiation sterilized products are also eaten by
thereby extending their shelf-life. For example, ripening astronauts in the NASA space shuttle programme because of
in bananas, mangoes,and papayas can be delayed by their superior quality, safety and variety, in preference to
irradiation at 0.25 to 1 kGy. Strawberries are frequently foods treated by other preservation techniques. Limited
spoiled by Botrytis mould. Treatment with a dose of 2 to 3 commercial-scale sterilization of various ready-to-eat foods by
kGy followed by storage at 10°C can result in a shelf-life of high dose irradiation has been carried out in South Africa
up to 14 days, but the extension obtained depends on the during the past 10 years to serve military personnel and

12 / Facts about food irradiation

outdoor enthusiasts such as campers, yachters and hikers.
In total, more than two million light weight food packs
(weighing 150 g each) have been produced during this period.

Disinfestation

The chief problem encountered in preservation of grains and

grain products is insect infestation. Most of the pests of
concern, e.g. beetles, moths, weevils and others, are not
quarantine insects, but they cause extensive damage to
stored products. Irradiation has been shown to be an effective
pest control method for these commodities and a good
Irradiation is an effective alternative to fumigation for insect control
alternative to methyl bromide, the most widely used fumigant
for insect control, which is being phased out globally because distributed by international trade in such fruits and also by
of its ozone depleting properties. Unlike methyl bromide, tourism. To prevent or minimize this risk, many countries pro-
irradiation is not an ozone depleting substance and unlike hibit importation of such fruits or require quarantine treatment
phosphine, the other major fumigant used to control grain of imported fruits. These measures can create significant
pests, irradiation is a fast treatment and its efficacy is not barriers to international trade and the free flow of plants and
temperature dependent. Irradiation can kill or control phos- plant products, but they are fully justified from the receiving
phine-resistant pests. The dosage required for insect control country’s point of view. The occurrence of fruit flies, such as
is reasonably low, in the order of 1 kGy or less. Disinfestation the Mediterranean, Oriental, Mexican or Caribbean fruit flies,
is aimed at preventing losses caused by insects in stored has repeatedly disrupted trade among countries and between
grains, pulses, flour, cereals, coffee beans, dried fruits, dried states within large countries, for example Australia and the
nuts, and other dried food products including dried fish. USA. A number of quarantine treatments permitted in the past
Proper packaging is required, however, for irradiated products have recently been banned, fumigation with ethylene dibro-
to prevent insect reinfestation. mide being the most prominent example. It has been de-
monstrated that low dosages of ionizing radiation, between
Radiation disinfestation can facilitate trade in fresh fruits, 0.15 and 0.3 kGy, will very effectively control fruit fly and other
such as citrus, mangoes, and papayas which often harbour insect problems. This makes the use of irradiation for quaran-
insect pests of quarantine importance. Insects are easily tine treatment a very practical possibility. In 1996, the United

Facts about food irradiation / 13

 shipments from other climatic zones, usually at a much higher
price, can replace local production during off-season. Such
long-term storage is possible with the aid of refrigeration,
which is costly, particularly in subtropical and tropical regions.
For many of these crops, the desired inhibitory effects can also
be obtained using chemical sprout inhibitors such as maleic
hydrazide, propham, or chloropropham. These chemicals,
however, are either not effective under tropical conditions or
leave residues in the produce, and for health reasons they are
Sprouting losses in stored potatoes can be prevented by irradiation considered by some to be harmful. Thus many countries have
prohibited their use.
States Department of Agriculture (USDA)/Animal and Plant
Health Inspection Service (APHIS) issued a Notice of Policy A very low radiation dose of 0.15 kGy or less, inhibits
accepting irradiation as a quarantine treatment against major sprouting of products such as potatoes, yams, onions, garlic,
species of fruit fly regardless of commodities. Subsequently, ginger, and chestnuts. It leaves no residues and allows
in 1997 a final rule was issued by the USDA/APHIS for the storage at higher temperatures. Irradiation of potatoes,
irradiation of papayas, carambola, and litchi as a phyto- stored at higher temperatures (10°-15°C), have better
sanitary treatment. The rule allows interstate movement of processing quality. Commercial processing of irradiated
these commodities from Hawaii to the USA mainland and potatoes has been carried out in Japan since 1973.
permits treatment either in Hawaii or in non-fruit fly
supporting areas of the mainland USA. Small commercial scale
irradiation of fruits from Hawaii has been carried out under But can irradiation be used to make spoiled
special permission of the USDA/APHIS since 1995. Such food good or to clean up “dirty” food?
irradiated fruits have been marketed successfully in the USA.
NO. Neither irradiation nor any other food treatment can
reverse the spoilage process and make bad food good. If food
Inhibition of sprouting already looks, tastes or smells bad – signs of spoilage –
before irradiation, it cannot be “saved” by any treatment
In order to provide consumers with a year-round supply including irradiation. While irradiation can reduce or
of potato tubers, onion bulbs, yams and other sprouting eliminate spoilage bacteria or pathogenic microorganisms
plant foods, storage over many months is necessary unless which may be present in a spoiled food, it cannot improve

14 / Facts about food irradiation

its sensory properties – the bad appearance, taste or smell Play it safe!
will remain.

Treatments such as heat pasteurization, chemical fumigation,

and irradiation, however, are effective in destroying or
suppressing microbial contamination of food. Heat pasteur- Pasteurization Irradiation
ization and fumigation have been effectively used in this way Safer Milk Safer Food
for decades to “clean up” foods, specifically to destroy patho-
IRRADIATED FOOD THE SAFE CHOICE
genic microorganisms in milk and other liquid products, and
to destroy spoilage microflora or microorganisms and insects
in spices and dry foods. These treatments are done intention- But is the use of this technology really
ally for public health reasons; for example, to destroy micro- necessary?
organisms such as Salmonella, Shigella, and Campylobacter
that are associated with food-borne diseases. Irradiation is A similar question was asked of pasteurization when it
especially effective as a control measure for pathogenic was first proposed as a means of improving the safety of
microorganisms transmitted through solid food, especially milk. Pasteurized milk was demonstrated to be safe,
foods of animal origin even when in the frozen state. practical and fit for the needs of most urban consumers. It
was very similar in taste and colour to fresh milk and
Food processes such as heating, freezing, chemical treat- required no change in consumption or cooking habits.
ment, and irradiation are not intended to serve as sub- However, the pasteurization of milk did not become a
stitutes for good hygienic practice. Both at the national commercial reality for many years after its introduction in
and international levels, good manufacturing practices the early 1900s. A similar situation has arisen with
(GMPs) govern the handling of specific foods and food irradiated food. Although the safety and benefits of food
products. They must be followed in the preparation of food, irradiation have been thoroughly documented, the com-
whether the food is intended for further processing by mercial application of the process has been hindered due
irradiation or any other means. An additional step in the to some misconception by the general public on its safety
further processing of food, such as irradiation, requires a and the conservative position of the food industry.
stricter adherence to GMP so that the products reach the
final stages at the highest possible quality level. Other processes such as chemical and heat treatments can
also kill insects, moulds and microorganisms, including
pathogens in food. However, chemicals can leave residues,

Facts about food irradiation / 15

and heating food, such as canning, changes its texture, Food irradiation has an important role to play in the
colour and flavour and converts it into a cooked product. production of safe, wholesome food just as heat-
Irradiation, on the other hand, achieves its effects without pasteurization has. At a time when the number of food
significantly raising the temperature of the food, leaving it poisoning outbreaks is on the increase, when fumigants
closer to the unprocessed state. Unlike the fumigants used are being phased out, and the consumer is looking for
for disinfestation and quarantine purposes, for example safer, higher quality foods, the overwhelming benefits of
ethylene oxide and methyl bromide, irradiation does not food irradiation cannot be overlooked. Irradiation helps to
leave residues in the food and is safer to use. Irradiation ensure a safer and more plentiful food supply by extending
is unique, however, in its ability to inactivate pathogenic shelf-life and controlling pests and pathogens in food.
microorganisms, such as Salmonella, E. coli O157:H7 and Most importantly, it is a safe process.
Campylobacter, in food in the frozen state, particularly in
food of animal origin.

Food Irradiation Applications

Benefit Dose (kGy) Products

Low-dose (up to 1 kGy)

(i) Inhibition of sprouting 0.05 - 0.15 Potatoes, onions, garlic, root ginger, yam etc.
(ii) Insect disinfestation and parasite disinfection 0.15 - 0.5 Cereals and pulses, fresh and dried fruits, dried
fish and meat, fresh pork, etc.
(iii) Delay of physiological processes (e.g. ripening) 0.25 - 1.0 Fresh fruits and vegetables.

Medium-dose (1-10 kGy)

(i) Extension of shelf-life 1.0 - 3.0 Fresh fish, strawberries, mushrooms etc.
(ii) Elimination of spoilage and pathogenic microorganisms 1.0 - 7.0 Fresh and frozen seafood, raw or frozen poultry
and meat, etc.
(iii) Improving technological properties of food 2.0 - 7.0 Grapes (increasing juice yield), dehydrated
vegetables (reduced cooking time), etc.

High-dose (10-50 kGy)

(i) Industrial sterilization (in combination with mild heat) 30 - 50 Meat, poultry, seafood, prepared foods, sterilized
hospital diets.
(ii)Decontamination of certain food additives 10 - 50 Spices, enzyme preparations, natural gum, etc
and ingredients

16 / Facts about food irradiation

 Fo o d I r ra d i at i o n Fa c i l i t i e s

What are the main features of a food products and can be either a conveyor or a rail system. In a
irradiation facility? gamma irradiator, the size of the containers in which the food
is moved through the irradiation chamber can vary and pallets
Industrial food irradiation facilities must be licensed, up to 1 m3 may be used. On the other hand, with machines,
regulated and inspected by national radiological safety and the bulk or thickness of a product which can be treated is
health authorities, many of whom base their rules upon much less and hence there is a fundamental design difference
irradiation standards and codes of practice jointly established between the two types of irradiator.
by the IAEA, FAO and WHO. The common features of all com-
mercial 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 Source Hoists
other industrial building is the concrete shielding (1.5 – 1.8
Source Pass Mechanism
metres thick) surrounding the irradiation room, which ensures
Radiation Room
that ionising radiation does not escape to the outside of the
Radiation
room. Shield
Unloading Area
In the case of a gamma irradiator, the radionuclide 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 Source in
Loading Area Control Console Storage Pool
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. Gamma Irradiator for food processing

The transport system employed in a large food irradiation

facility is similar to that used for sterilization of medical

Facts about food irradiation / 17

 processing food. For example, the principle of lot traceability
is an essential part of process controls, whether the product
is a pharmaceutical or a fruit, and irrespective of the tech-
nology involved.

At the international level, provisional guidelines for good

manufacturing practices (GMPs) and good irradiation practices
for a number of foods have been issued by the International
Consultative Group on Food Irradiation (ICGFI). They cover all
aspects of treatment, handling, and distribution. These guide-
lines provide a good basis for preparing the detailed protocols
needed to implement irradiation on a commercial scale. Some
of the guidelines have converted to standards of the American
Society for Testing and Materials (ASTM).

The guidelines emphasise that, as with all food technologies,

Electron beam irradiator for food processing
effective quality control systems need to be installed and
adequately monitored at critical control points at the
irradiation facility. Foods should be handled, stored, and
How can we be sure that foods are properly transported according to good manufacturing practices
treated in irradiation facilities? (GMPs) before, during, and after irradiation. Only high-quality
food should be accepted for irradiation.
Over the past 30 years, laws and regulations have been
promulgated to govern operations at industrial irradiators The Codex Alimentarius Commission of FAO and WHO adopted
used to process non-food products, such as medical supplies. in 1983 a Codex General Standard for Irradiated Foods, and
About 170 such irradiators are operating around the world. an associated International Code of Practice for the Operation
The plants, which must be approved by governmental of Radiation Facilities Used for the Treatment of Foods. These
authorities before construction, are subject to regular standards state that irradiated foods should be accompanied
inspections, audits, and other reviews to ensure that they by shipping documents identifying the irradiator, date of treat-
are safely and properly operated. These types of govern- ment, lot identification, dose, and other details of treatment.
mental controls would also be valid for irradiation facilities ICGFI additionally has established an international registry of

18 / Facts about food irradiation

irradiators that meet standards for good operations. It also
organizes training courses for irradiator operators, plant
managers, and supervisors on proper processing, with
emphasis on GMPs, dosimetry, record-keeping, and lot identi-
fication, and for food control officials on proper inspection
procedures required for food irradiation processing and trade
in irradiated foods.

Do workers at irradiation facilities face dangers

from long-term or accidental exposure to
radiation?

Any industrial activity includes certain risks to human beings Processing of food by irradiation can be safely monitored and controlled
and the environment. One of the risks at irradiation facilities
is associated with the potential hazard of accidental exposure dangers: “...the risk is kept under effective control by the use
to ionizing radiation. Irradiators are designed with several of sophisticated safety control systems. The plants are
levels of redundant protection to detect equipment mal- constructed with very heavy radiation shielding and thus the
function and to protect personnel from accidental radiation process presents no risk to the general public. We do not
exposure. Under normal operating conditions, all exposures expect that the legalisation of foodstuffs irradiation will
of workers to radiation are prevented because the radiation present any novel health and safety issues within our area of
source is shielded. Potentially hazardous areas are monitored interest”.
and a system of interlocks prevents unauthorized entry into
the radiation room while products are being irradiated. Worker
safety further rests upon strict operating procedures and Have there been any major accidents at
proper training. All radiation plants must be licensed. In most industrial irradiation facilities?
countries, regulations require periodic inspection of facilities
to ensure compliance with the terms of operating licenses. In Over the past 30 years, there have been a few major
the United Kingdom, the Health and Safety Executive has accidents at industrial irradiation facilities that caused
reported to a parliamentary committee that personnel working injury or death to workers because of accidental exposure
in the country’s 10 irradiation facilities face no unusual to a lethal dose of radiation. All of the accidents happened

Facts about food irradiation / 19

because safety systems had been deliberately bypassed More radioactive materials will need to be
and proper control procedures had not been followed. transported if more food irradiators are built.
None of these accidents endangered public health and What steps have been taken to minimize the
environmental safety. danger of radioactive spills from transport
accidents?
In most cases, reports of “accidents” have actually turned
out to be operational incidents. Such incidents have Radioactive materials required for irradiators is
caused the irradiator to be shut down but they did not transported in lead-shielded steel casks. These casks meet
harm anyone or pose a risk to the environment. The national and international standards modelled upon the
distinction between accidents and incidents is used by Regulations for Safe Transport of Radioactive Materials of
authorities responsible for safety in all industries. This is the International Atomic Energy Agency (IAEA) and are
the case for many other food technologies, such as designed to withstand the most severe accidents,
canning, fumigation and the agro-chemical industry, which including collisions, punctures, and exposure to fire and
are also potentially hazardous to workers. At irradiation water depths. Large quantities of radioactive material are
facilities, controls and formal protocols are strictly required safely shipped all over the world to supply some 170
to prevent accidents. irradiators processing a variety of goods, mainly medical
products such as syringes, physician gloves, sutures, and
The radiation processing industry is considered to have a hospital gowns. From 1955 to date, Canada has shipped
very good safety record. Today there are about 170 approximately 480 million curies of cobalt-60 without any
industrial gamma irradiation facilities operating world- radiation hazard to the environment or release of
wide, a number of which process food in addition to other radioactive materials. Over the same period, approximately
types of products. Most irradiation facilities are used for one million shipments of radioisotopes for industrial,
sterilizing disposable medical and pharmaceutical hospital, and research use were made in North America
supplies, and for processing other non-food items. without radiation accidents. This excellent safety record far
Facilities are constructed to standard designs with multiple exceeds that of other industries shipping hazardous
safeguards to protect worker health and safeguard the materials such as toxic chemicals, crude oil, or gasoline.
community should a natural disaster such as an The same procedures used so successfully and safely to
earthquake or tornado occur. transport radioactive materials to existing irradiators will

20 / Facts about food irradiation

of course be used for transporting radioactive materials to typically cobalt-60 or cesium-137, are used as the sources of
any additional irradiators constructed for food processing. radiation energy. These elements decay over time to non-
radioactive nickel and non-radioactive barium, respectively.
The sources are removed from the irradiator when the
Can an accident at a gamma irradiation facility radioactivity falls to a low level, usually between 6% and
lead to “meltdown” of the irradiator and release 12% of the initial level (this takes 16 to 21 years for cobalt-
of radioactivity that would contaminate the 60). The elements are then returned in a shipping container
environment and endanger people living nearby? to the supplier who has the option of reactivating them in
a nuclear reactor or storing them. It has been estimated
It is impossible for a “meltdown” to occur in a gamma that when the useful life of the cobalt-60 is finally over, all
irradiator or for the radiation source to explode. The source the used cobalt-60 produced in North America could be
of radiation energy used at irradiators cannot produce stored in a space of about 1.25 cubic metres, which is
neutrons which can make materials radioactive, so no roughly equivalent to the size of a small office desk.
nuclear "chain reaction” can occur at an irradiator. The walls
of the irradiation cell through which the food passes, the Basically, the same procedures are followed when an
machinery inside the cell, and the product being processed irradiation plant closes down. The sources can be acquired
cannot become radioactive. No radioactivity is released into by another user or returned to the supplier, the machinery
the environment. dismantled, and the building used for other purposes.
There is no radiation hazard for the new occupants or the
general public.
Do gamma irradiators have radioactive waste
disposal problems?

It is a misconception that the existence of gamma irradiation

facilities will lead to a growing accumulation of radioactive
waste material. At gamma irradiators, radionuclide sources,

Facts about food irradiation / 21

 S a fe t y o f I r ra d i at e d Fo o d

Does the irradiation process make food

radioactive?

NO. Irradiation does not make food radioactive. Everything in

our environment, including food, contains trace amounts of
radioactivity. This means that this trace amount (about 150 to
200 becquerels/kg) of natural radioactivity from
elements such as potassium is unavoid-
able in our daily diets. In countries where
food irradiation is permitted, both the
sources of radiation and their energy levels
Irradiation does not induce radioactivity in food just as fruit exposed to sun
are regulated and controlled. The irradiation energy does not emit sunlight
process involves passing the food through a
radiation field at a set speed to control the What is the difference between the terms
amount of energy or dose absorbed by the food. The “irradiated food” and “radioactive food”?
food itself never comes into direct contact with the radiation
source. The maximum allowable energies for electrons and X- Irradiated foods are those that have been deliberately
rays from the two machine-generated sources of radiation processed with certain types of radiation energy to bring
that can be used, are 10 million electron volts (MeV) and 5 about some desirable properties (for example, to inhibit
MeV, respectively. Even when foods are exposed to very high sprouting or to destroy food-poisoning bacteria). Apart from
doses of radiation from these sources, the maximum level of foodstuffs, many other materials are commercially irradiated
radioactivity would be just one-thousandth of a becquerel per during manufacturing. These include cosmetics, wine bottle
kilogram of food. This is 200,000 times smaller than the level corks, hospital supplies and medical products, and some
of radioactivity naturally present in food. Food undergoing types of food packaging. Radioactive foods, on the other
irradiation does not become radioactive any more than hand, are those that have become accidentally contaminated
luggage passing through an airport X-ray scanner or teeth by radioactive substances from weapons testing or nuclear
that have been X-rayed. reactor accidents. This type of contamination is totally

22 / Facts about food irradiation

unrelated to irradiated food which has been processed for
preservation and other purposes.

Can irradiated food become toxic?

NO. Since the late 1940s irradiated foods were considered

to require careful toxicological investigation before this
process could be applied to food manufacturing. In actual
fact it was firmly concluded by a study conducted in
Germany as far back as 1926 that irradiation did not
produce any toxic factors in animal diets. The standard The wholesomeness of irradiated food is well established
procedure for this purpose was to feed the foodstuff to be
tested to laboratory animals and look for possible effects of evaluated for the WHO in 1992 all literature and data which
longevity, reproductive capacity, tumour incidence, and had been available since 1980; as a consequence, the
other indicators of the animals’ health status. previous findings were reconfirmed. During September 1997 a
study group meeting was organised jointly by the WHO, FAO
Several hundred toxicological studies have been conducted and IAEA to evaluate the wholesomeness of food treated by
on experimental animals over the past four decades. Many high dose irradiation. This group of experts concluded that
animal feeding tests including genetic studies of different doses greater than 10 kGy “will not lead to changes in the
types of irradiated food were carried out in many countries composition of the food that, from a toxicological point of
including China, Germany, India, Japan, Thailand, the United view, would have an adverse effect on human health”.
Kingdom and the USA in the past five decades. FAO, IAEA and
WHO convened a number of Joint Expert Committees on the Among the many extensive animal feeding studies of
Wholesomeness of Irradiated Foods in 1964, 1969, 1976 and irradiated food, those conducted at the Raltech Laboratory,
1980 as data became available to evaluate the safey for USA, are generally acknowledged to be among the best and
consumption of irradiated foods. These evaluations together most statistically powerful of all. The studies involved using
with those carried out independently by national expert chicken irradiated either by a cobalt-60 source or electron
groups in Denmark, France, the Netherlands, Japan, the United machine up to a dose of 58 kGy. Some 134 tonnes of chicken
Kingdom and the USA demonstrated no toxic effects as a meat, or nearly a quarter of a million birds, were used
result of consuming irradiated food. Another expert committee in the study to compare high-dose irradiation with heat-

Facts about food irradiation / 23

sterilization of chicken. The study involved chronic feeding ploidy”, which is alleged to result from consumption of
studies in mice and dogs, teratology studies and muta- products made from wheat immediately after irradiation.
genicity tests. The comprehensive results were reviewed by Polyploidy means the occurrence of cells containing twice
scientists of the United States Food and Drug Administration or more the number of chromosomes. Human cells
(FDA) at the time a petition for low dose irradiation of normally have 46 chromosomes. If they are polyploid they
chicken was submitted in the mid-1980s. No adverse effects could have 92 or even 138 chromosomes. The incidence of
from consuming chicken processed with high doses of polyploid cells is naturally occurring and varies among
radiation were reported. The lack of treatment-related effects individuals, and even in one individual from day to day. It
in the many well-conducted studies provides additional can also vary from organ to organ within one individual.
assurance that the consumption of irradiated food does not The biological significance of polyploidy is unknown. When
pose a hazard. undertaking studies on polyploidy, it is important that
many thousands of cells are counted in order to see the
Other types of extensive feeding tests also have been done. effect of a treatment. As polyploid cells are rare, it is
Over the last 20 years millions of mice, rats, and other essential that enough cells are observed before any valid
laboratory animals have been bred and reared exclusively conclusions can be reached. It can also be extremely
on an irradiated diet. The diet, treated at doses between 25 difficult to recognise polyploid cells; if normal (diploid)
and 50 kGy, has been fed to laboratory animals at many cells happen to be superimposed on the microscope slide
institutions involved in food, drug, and pharmaceutical re- they look very much like one polyploid cell.
search in Austria, Australia, Canada, France, Germany, Japan,
Switzerland, the United Kingdom, and the USA. No trans- Media reports have frequently cited results published in
mittable genetic defects – teratogenic or oncogenic – have the mid-1970s by a group of scientists from the National
been observed which could be attributed to the con- Institute of Nutrition (NIN) in Hyderabad, India. This group
sumption of irradiated diets. of scientists reported increases in the frequency of
polyploid cells in malnourished children, rats, mice and
monkeys that they attributed to consumption of products
Can eating irradiated food cause development made from wheat immediately after irradiation at 0.75 kGy.
of abnormal chromosomes? When the report is examined more closely, among other
shortcomings, it is found that only 100 cells from each of
NO. The issue of abnormal chromosomes as a result of the five children in each group were counted – an
eating irradiated food has been more sensationalised than incredibly small sample upon which to base any
any other. The claims focus on the incidence of “poly- conclusion. In addition, although the results in each group

24 / Facts about food irradiation

were averaged, there is no indication of the actual Besides feeding tests using laboratory animals,
incidence in each child. No polyploidy at all was seen have there been any human feeding studies of
when wheat was irradiated and stored for 12 weeks before irradiated foods?
consumption.
YES. In the early 1980s, eight feeding studies using several
A number of institutions in India and elsewhere have tried irradiated food items, including irradiated wheat, were
to reproduce the results found at NIN based on in- conducted in China using human volunteers. More than 400
formation made available to them. Some used absorbed individuals consumed irradiated food under controlled con-
radiation doses as high as 45 kGy. For example, a rat ditions for 7 to 15 weeks. One focus of the research was the
feeding study carried out at the Bhabha Atomic Research possibility of chromosomal changes. Seven of the eight ex-
Centre (BARC) in Mumbai, with freshly irradiated wheat, in periments involved investigation of chromosomal aberrations
which the incidence of polyploidy was determined by in 382 individuals. No significant difference between the
counting 3,000 cells from each animal, showed no effect number of chromosomal aberrations in the control and test
from consuming the irradiated wheat. groups were discovered in any of the experiments. Incidence
of polyploidy in those who consumed non-irradiated food and
None of the studies carried out came up with results those who consumed irradiated samples were within normal
similar to those found at NIN. In order to investigate the range of the overall value of polyploid cells in participants.
reasons for the discrepancy between the results reported
by the researchers in Hyderabad and Mumbai a committee Although not aimed at testing the safety of irradiated foods it
of experts was appointed by the Indian government in is worth noting at this point that radiation-sterilized foods are
October 1975 to review the findings. In 1976, the report of used in the diet of severely ill patients. A number of hospitals
the Committee was very critical of the work of the in the USA and the United Kingdom used irradiated foods for
Hyderbad authors and concluded that the available data patients who have to be kept in a completely sterile environ-
failed to demonstrate any mutagenic potential of ment due to their susceptibility to bacterial or viral infections.
irradiated wheat. A number of national scientific com- Patients undergoing chemotherapy, or organ transplant
mittees and independent researchers in Australia, Canada, patients who receive immunosuppressive medication may
Denmark, France, the United Kingdom, and the USA also be fed only sterilized foods for weeks or even months.
have evaluated the alleged incidence of polyploidy. They Supplementing heat-sterilized foods with radiation-sterilized
all concluded that the study was simply unacceptable and items can provide more varied, more palatable, and more
the reported data from NIN do not support the incidence nutritious menus for these patients. Irradiated foods were fed
of increased polyploidy. to such patients at the Fred Hutchinson Cancer Research

Facts about food irradiation / 25

 Do the “free radicals” which are produced
during irradiation affect the safety of the food?

NO. The fact that irradiation causes the formation of free

radicals – which in scientific terms are atoms or molecules
with an unpaired electron – and that these are quite stable
in dry foods has often been mentioned as a reason for
special caution with irradiated dry foods. However, free
radicals are also formed by other food treatments, such as
“Radiolytic” products formed in irradiated foods are similar to
toasting of bread, frying, and freeze drying, and during
products formed by cooking (“thermolytic products”)
normal oxidation processes in food. They are generally
Center, Seattle, USA for several years during the mid 1970s very reactive, unstable structures, that continuously react
with excellent results. with substances to form stable products. Free radicals
disappear by reacting with each other in the presence of
liquids, such as saliva in the mouth. Consequently, their
Are chemical changes in irradiated foods, such as ingestion does not create any toxicological or other
the formation of “radiolytic” products, harmful? harmful effects.

The so-called “radiolytic” products produced in irradiated This has been confirmed by a long-term feeding study
food have proven to be familiar ones, such as glucose, formic carried out a the Federal Research Centre for Nutrition in
acid, acetaldehyde, and carbon dioxide, that are naturally Karlsruhe, Germany. This study was especially designed to
present in foods or are formed by thermal processing (thermo- look for possible effects of a diet containing a high free
lytic products). The safety of these radiolytic products has radical concentration. Animals were fed a very dry milk
been examined very critically, and no evidence of their powder irradiated with electrons at 45 kGy. No mutagenic
harmfulness has been found. effects were noted and no tumours were formed. Nine
generations of rats were continually fed this diet without
The United States Food and Drug Administration (FDA) has any indication of toxic effects. Similarly, a slice of toasted
estimated that the total amount of undetected radiolytic bread (non-irradiated), which actually contains more free
products that might be formed when food is irradiated at a radicals than very dry foods that have been irradiated, can
dose of 1 kGy would be less than 3 milligrams per kilogram be expected to be harmless.
of food or less than 3 parts per million.

26 / Facts about food irradiation

Can irradiation of food increase the risk of including irradiation, must be kept at 3° C or below at all
botulism? times during marketing. Most other types of Clostridium
botulinum cannot grow and produce toxin at temperatures
Under Good Manufacturing Practices (GMPs), irradiating food below 10° C. Good manufacturing practices (GMPs) require
of animal origin to ensure its hygienic quality does not that raw foods such as fish, meat, and chicken are stored at
increase the risk from botulism any more than other “sub- a specific temperature, whether irradiated or not, to prevent
sterilizing” food processes, such as pasteurization. It is true the growth of Clostridium botulinum. It has been concluded
that bacterial spores such as those of Clostridium botulinum by various workers in this field of research that low-dose
are resistant to most preservation treatments, including low irradiation does not increase the risk from sporogenous
doses of irradiation. However, these spores are usually bacteria. On the contrary, it has been emphasised that low-
present in relatively low numbers and, although they survive dose irradiation can increase the safety of foods.
sub-sterilizing doses of irradiation, other microorganisms also
survive irradiation can grow, cause spoilage and inhibit the
growth of Clostridium botulinum. The survival of spores is Are foods in which microbial toxin or viruses
therefore not considered to introduce any additional hazard in are already present suitable for irradiation?
irradiated foods than in food subjected to other sub-sterilizing
heat-treatments, for example, in pasteurized or cooked foods. NO. Only foods of good hygienic quality should be
irradiated. In this respect, irradiation does not differ from
Food treated by irradiation or traditional pasteurization must heat pasteurization, freezing, or other food processes.
be handled, packaged, and stored following good manu- While these processes can destroy bacteria, they may not
facturing practices (GMPs). Doing so prevents the growth and destroy preformed toxins and viruses already in the food.
toxin production of Clostridium botulinum. Alternatively, high- It is very important that foods intended for processing
dose irradiation (30-60 kGy) can be used to destroy any – by whatever method – are of good quality and handled
Clostridium botulinum spores present in the food. and prepared according to GMPs established by national
or international authorities. In some cases, strict regu-
Some types of clostridia cause more concern than others. lations prohibit distribution of some foods. Many
Clostridium botulinum Type E, for example, is found at low countries, for example, do not permit oysters to be
levels in fish and seafood caught in some areas. It can grow harvested from areas known to be contaminated with raw
and produce toxin even when the food is refrigerated at sewage because of the danger of hepatitis viruses. No
temperatures as low as 4° C. Thus, fish and seafood, including food processing methods should be used to substitute for
their products, treated by any of the sub-sterilizing processes, GMPs in food production and handling.

Facts about food irradiation / 27

 N u t r i t i o n a l Q u a l i t y o f I r ra d i at e d Fo o d s

Does irradiation adversely affect the nutritional and fats, undergo little change during irradiation even at
value of food? doses over 10 kGy. Similarly, the essential amino acids,
minerals, trace elements and most vitamins do not suffer
NO more so than any other methods of food processing and significant losses.
preservation used to achieve the same purpose. As irradiation
is a ‘cold process’, that is, it does not substantially raise the Different types of vitamins have varied sensitivity to
temperature of the food being processed, nutrient losses are irradiation and to some other food processing methods. The
small and often significantly less than losses associated with sensitivity of the vitamins to irradiation depends on the
other methods of preservation such as canning, drying complexity of the food system and the solubility of the
and heat pasteurization. Much of the early work on irradiation vitamins in water or fat. Irradiation of vitamins in pure
examined foods treated at sterilizing doses, solution results in considerable destruction of these
but since recent applications often use compounds thus some reports in literature have over-
doses well below 10 kGy, a realistic estimated the losses. For example, vitamin B1 (thiamin) in
evaluation of the nutritional adequacy aqueous solution showed 50% loss after irradiation at 0.5
of irradiated food should be based kGy, while irradiation of dried whole egg at that dose caused
on results of experiments carried out less than 5% destruction of the same vitamin. This is due to
using doses likely to be used in the mutually protective action of various food constituents
commercial practice. The change in nutritional value caused on each other. Vitamin losses can be minimized by irradiating
by irradiation depends on a number of factors. These include the food in frozen form or by packaging it in an inert
the irradiation dose to which the food has been exposed, the atmosphere such as under nitrogen.
type of food, packaging, and processing conditions, such as
temperature during irradiation and storage time. Four vitamins are recognised as being highly sensitive
to irradiation: B1, C (ascorbic acid), A (retinol) and E
Carbohydrates, proteins and fats are the main components (a-tocopherol). However, B1 is even more sensitive to heat
of foods. These macronutrients provide energy and serve as than to irradiation. It has been demonstrated that pork
building blocks for the growth and maintenance of the body. and beef sterilized by irradiation retain much more vitamin
Extensive research has shown that carbohydrates, proteins, B1 than canned meat sterilized thermally.

28 / Facts about food irradiation

Seemingly conflicting results of low versus high losses of
vitamin C for some irradiated foods may be attributed to
differences in analytical approaches used by researchers.
Some have measured only ascorbic acid, while others have
measured total ascorbic acid, a mixture of ascorbic acid and
dehydroascorbic acid. Both acids have vitamin C biological
activity and are easily transformed from one to the other. If
only ascorbic acid were measured, any apparent reduction in
vitamin C level would be exaggerated. Research has shown
that the natural differences in total vitamin C content of four
varieties of strawberry are much greater than the reduction Irradiation does not significantly change the nutritive value of food
which occurs on irradiation. With, for example, potatoes it
has been demonstrated that although irradiation does reduce substantiated by the results of many feeding studies which
vitamin C content, cooking and storage also have a significant have been undertaken to establish the wholesomeness
effect. The benefit of irradiating potatoes is to inhibit of irradiated food. It should also be remembered that
sprouting during storage. Following six months of storage irradiated food will be consumed as part of a mixed diet,
the vitamin C content of irradiated and unirradiated potatoes and therefore the process will have little impact on the
have been shown to be similar. Since the optimal dose for total intake of specific nutrients.
irradiation treatment of fruit and vegetables, is generally
below 2 kGy, effects on vitamin C at higher doses are The Joint Expert Committee of the Food and Agriculture
irrelevant. Organization (FAO), World Health Organization (WHO), and
International Atomic Energy Agency (IAEA), which examined
The significance of any losses of vitamins E and A due to these and other issues, stated in its conclusions in 1980 that
irradiation are marginal because the main sources of these irradiation does not introduce special nutritional problems in
vitamins in the human diet are butter and milk and these are food. This was also the finding of the group of experts who
unsuitable for irradiation treatment. Irradiation has practically convened at a meeting organised by the FAO, IAEA and WHO
no effect on the levels of beta carotene and other carotenoids, in Geneva, Switzerland in 1997 to discuss the effects of high
the precursors of vitamin A, formed in fruits during ripening. dose irradiation. It was concluded at this meeting that doses
greater than 10 kGy “will not lead to nutrient losses to an
On the whole, the effects of irradiation on the nutritional extent that would have an adverse effect on the nutritional
value of foods are minimal and these observations are status of individuals or populations”.

Facts about food irradiation / 29

 Pa c ka g i n g o f I r ra d i at e d Fo o d s
With the exception of such applications as sprout inhibition intended for irradiation has been studied in Canada, the
in potatoes or onions, insect disinfestation in bulk grains, United Kingdom, the USA, and a few other countries. A
or delay of post-harvest ripening of fruits, irradiation of number of food packaging materials were approved for use
foodstuffs is usually carried out on packaged food items. in food irradiation by the United States Food and Drug
There may be different reasons for this: prevention of Administration (FDA) more than 20 years ago. More recently,
microbial reinfection or insect exposure, prevention of Canada, India and Poland have approved additional
water loss, exclusion of oxygen, prevention of mechanical materials, including a multi-layered polyethylene film, as
damage during transport, or simply improved handling and safe for packaging foods to be irradiated.
marketing. The packaging material used must not
release radiation-induced reaction products or Sophisticated tests have been used to evaluate the effect
additives onto the food, nor should it lose of radiation on plastic and other types of packaging
functional qualities such as mechanical materials. Researchers looked at the post-irradiation
strength, seal stability, or imper-
meability to water upon irradiation.

Is there any risk in irradiating foods in contact

with plastic or other packaging materials?

NO. Results of extensive research have shown that almost

all commonly used food packaging materials tested are
suitable for use at any dose likely to be applied to food
including sterilization treatment. Only packaging materials
which have been specifically authorized for such use may
be subjected to irradiation of prepackaged foods.

Various types of packaging materials have been approved Most commonly used food packaging materials are suitable for irradiated
for use when food is irradiated. Their suitability for food foods

30 / Facts about food irradiation

stability, mechanical strength, and permeability to water Other aseptic packaging materials, dairy product packaging,
and gases of the packaging materials, and at the extract- single-serving containers (for example, for cream), and wine
ability of the plastics, additives, and adhesives. bottle corks are also routinely sterilized by irradiation prior
to filling and sealing to prevent product contamination.

Are irradiated materials used to package foods? Other types of materials used to wrap food or other
products also are routinely processed by radiation in many
YES. Plastic films laminated with aluminium foil are routinely countries. The radiation process is used to "cross-link” the
sterilized by radiation as part of the manufacturing process. material’s polymer chains for greater strength and heat
They are used for hermetically sealed “bag-in-a-box” resistance, and for producing plastics with special
products, such as tomato paste, fruit juices, and wines. properties (for example, heat-shrink wrap).

Facts about food irradiation / 31

 Fo o d I r ra d i at i o n Co s t s
Will irradiation increase the cost of food? sprouts in potatoes and onions) to US $100 to $250 per
tonne for a high-dose application (for example, to ensure
Any food process will add cost. In most cases, however, hygienic quality of spices). These costs are competitive
food prices do not necessarily rise just because a product with alternative treatments. In some cases, irradiation can
has been treated. Many variables affect food costs, and one be considerably less expensive. For disinfestation of fruit
of them is the cost of processing. Canning, freezing, to satisfy the quarantine requirements of an importing
pasteurization, refrigeration, fumigation, and irradiation add country, for example, it has been estimated that the cost
cost to the product. These treatments will also bring benefits of irradiation would be only 10% to 20% of the cost of
to consumers in terms of availability and quantity, storage vapour-heat treatment.
life, convenience, and improved hygiene of the
food. Reduced losses will bring revenue to Electron beam irradiators may have economic advantages
producers and traders, thus in turn, over gamma irradiators where product throughput is large,
compensating treatment costs. the particle size or thickness of the product being treated
is small, and where continuous treatment is possible by
The major factors influencing the integrating the irradiator into the production line. As a
economics of food irradiation using result, they may be more efficient than gamma irradiators
cobalt-60 include: irradiation design for treating large volumes of domestic or imported grains.
parameters such as applied dose, In addition, these machine-type irradiators, based on
packing density of the products, handling electron acceleration rather than radionuclides, may not
conditions (dry versus perishable products), dose require as extensive regulatory approvals.
uniformity and throughput; capital costs consisting of the
irradiator, radiation source, spare parts for linear
accelerators, warehouse capacity; and operating costs How much does a typical food irradiation
such as salaries, utilities, replenishments of cobalt-60, facility cost?
maintenance, etc.
The cost to build a commercial cobalt-60 food irradiation
Irradiation costs range from US $10 to $15 per tonne for a plant is in the range of US $3 million to $5 million,
low-dose application (for example, to inhibit the growth of depending on its size, processing capacity, and other

32 / Facts about food irradiation

factors. This is within the range of plant costs for other other treatments. Commercial contract multipurpose-
technologies. For example, a moderately-sized, ultra-high irradiators operate in many countries offering irradiation
temperature plant for sterilizing milk, fruit juices, and other services at reasonable cost. Most of these facilities
liquids costs about US $2 million. A small vapour-heat successfully combine irradiation of various food products
treatment plant for disinfestation of fruits costs about and treatment of other non-food items such as cosmetics,
US $1 million. pharmaceutical and disposable medical products. Since
irradiation gives the added economic benefit of prolonged
Often the capital costs of irradiation equipment are seen fresh market life for many foods, decreased waste and
as prohibitive, even though low operating costs for most increased market potential of the food should be
commodities make per unit costs very competitive with considered in a cost-benefit analysis.

Irradiation costs only a fraction of that of the product

Facts about food irradiation / 33

 Tra d e i n I r ra d i at e d Fo o d s

Food imports and exports are important to the health and Fresh fruits and vegetables could be irradiated to overcome
economy of nations and people, yet trade barriers caused quarantine barriers against fruit flies in the near future. The
by pests, diseases and food safety issues continually United States Department of Agriculture (USDA) has accepted
threaten or inhibit trade. Several technologies work to irradiation as a quarantine treatment against major fruit fly
remove trade barriers. Irradiation is one such technology species regardless of host. A policy to this effect was issued
that could assist in the improvement of trade. by the USDA in 1996. Phytosanitary guidelines for the use of
irradiation as quarantine treatment will likely be applied in
other countries. South East Asia, for example, is in the process
Are irradiated foods being of implementing a harmonized protocol on the use of irradia-
traded internationally? tion as a quarantine treatment of horticultural commodities.

Some irradiated foods such as spices

and dried vegetable seasonings, as Will irradiated foods be labelled?
well as food ingredients such as
mechanically deboned poultry meat, Some national regulations require that irradiated food be
have entered international commerce for use labelled with a statement indicating the treatment and, often,
mainly by the food industry in various types of processed with an international logo known as the radura symbol.
food. The nature of the spice trade requires that spices, for Experience with market trials and commercial sale of
example pepper from various sources, be mixed to achieve irradiated food has proven that informed consumers are not
certain grades to satisfy market demand. Thus, it is possible against irradiated food but prefer it to be labelled as such.
that only a portion of the spices within one single shipment The label provides consumers with the opportunity to choose.
has been irradiated. The production of, and trade in, Label statements can also be used to state why products are
irradiated spices have increased significantly in recent years irradiated. It has been demonstrated that people are more
from about 5,000 tonnes in 1990 to over 30,000 tonnes in likely to buy irradiated food labelled with a statement
1994 to over 60,000 tonnes in 1997. Approximately 30,000 conveying the positive benefits of the technology, for
tonnes of irradiated spices and dried vegetable seasonings example, ‘Irradiated to control microbes’ or ‘Irradiated to
were produced in the USA alone in 1997. retard spoilage’.

34 / Facts about food irradiation

For irradiated foods that are not packaged, such as bulk
containers of fruit and vegetables, retailers in some
countries are required to display the logo and phrase.
Labelling regulations do, however, differ between
countries. For example, in the USA, labelling requirements
apply only to whole foods that have been irradiated but
not to irradiated ingredients in a food. In the European
Union it is proposed that food containing irradiated
ingredients such as spices, but which are not themselves
irradiated, must be labelled regardless of the percentage
of irradiated product which has been incorporated.

Many governments have introduced regulations requiring

labelling of irradiated food but not to those treated by
competitive treatments such as fumigation. However, in
August 1998 the United States Food and Drug Administration
Trade in irradiated food is happening
(FDA) amended the labelling requirements for irradiated
food – a statement disclosing irradiation treatment is not regulations that are stricter than the only recognized
required to be any more prominent than the declaration of international standards for food, which are the guidelines,
ingredients. and recommendations of the Codex Alimentarius Commis-
sion (food safety), the International Plant Protection
Convention (IPPC) (plant protection and quarantine), and
Can a government deny entry of irradiated the International Office of Epizootics (animal health and
food into its country? quarantine). With the existence of the Codex General
Standard for Irradiated Foods, which recognizes the safety
A government can deny entry of any product into its and effectiveness of food irradiation, and the endorsement
territory. However, under the provision of the Agreement of irradiation as a quarantine treatment of fresh agri-
on the Application of Sanitary and Phytosanitary Measures cultural produce by regional plant protection organizations
(SPS), being enforced by the World Trade Organization operating within IPPC, irradiated food treated according to
(WTO), such a government (if a member of WTO) may be the principle of the Codex Standard can no longer be
requested to furnish scientifically-based justification for denied entry into countries on scientific grounds.

Facts about food irradiation / 35

 D e t e c t i o n M e t h o d s fo r I r ra d i at e d Fo o d

Are detection methods for irradiated foods the facility can be supplemented by an additional means
necessary? of enforcement, thus facilitating international trade and
reinforcing consumer confidence in the overall process”.
The need for reliable and routine tests to determine
whether or not food has been irradiated arose as a result
of the progress made in commercialisation of the food Are reliable detection methods available at
irradiation process, greater inter- present to determine whether or not food has
national trade in irradiated foods, been irradiated?
differing regulations relating to the
use of the technology in many YES. Since the mid 1980s extensive research has resulted
countries, and consumer demand in the development of a range of tests which can be used
for clear labelling of the treated to reliably determine the irradiation status of a wide
food. Although not essential for variety of food. The methods which have been studied
management of the process, it was most extensively and which have the greatest scope
envisaged that the availability of such of application include electron spin resonance (ESR)
tests would help strengthen national regulations on spectroscopy, thermoluminescence (TL), and monitoring
irradiation of specific foods, and enhance consumer the formation of long-chain hydrocarbons and 2-alkylcy-
confidence in such regulations. The availability of reliable clobutanones. These methods have been successfully
identification methods would be of assistance in evaluated in a number of interlaboratory blind trials with
establishing a system of legislative control, and help to the result that, in 1996, five tests were adopted as
achieve acceptance of irradiated foods by consumers. In standard reference methods for the detection of irradiated
fact, an International Conference on Acceptance, Control food by the European Committee for Normalisation (CEN).
of, and Trade in Irradiated Food held in Geneva in 1988 These in turn are being adopted by some national
recommended that “governments should encourage authorities, such as Germany and the United Kingdom.
research into methods of detection of irradiated foods so More tests are being considered by CEN for imple-
that administrative control of irradiated food once it leaves mentation as reference methods.

36 / Facts about food irradiation

Standard methods for the detection of irradiated foods 20
adopted by the European Committee for Normalization Irradiated (6kGy)
(CEN) in December 1997 18
Unirradiated
16
Number Title

N U M B E R O F O B S E RVATI O N S
14
en 1784 Foodstuffs - Detection of irradiated food containing
12
fat - Gas chromatographic analysis of hydrocarbons
en 1785 Foodstuffs - Detection of irradiated food containing 10
fat - Gas chromatographic / Mass spectrometric
analysis of 2-alkylcyclobutanones 8
en 1786 Foodstuffs - Detection of irradiated food containing 6
bone - Method by ESR spectroscopy
en 1787 Foodstuffs - Detection of irradiated food containing 4
cellulose - Method by ESR spectroscopy
en 1788 Foodstuffs - Detection of irradiated food from which
2
silicate minerals can be isolated - Method by 0
Thermoluminescence. 10-1 100 101 102 103 104 105 106 107 108 109
PSL/PHOTON COU NTS

Based on “Detection Methods for Irradiated Foods”, The Royal Society of

Chemistry 1996.

Facts about food irradiation / 37

 I r ra d i at e d Fo o d s a n d t h e Co n s u m e r

The ultimate test for any product or process is the market ments by a respected health authority increase their
place, as it is the consumer who determines whether or confidence in the safety of this technology. A United States
not a product is better than previous or competitive Department of Agriculture (USDA) funded project in California
products. Such is the case for irradiated food which, at the and Indiana evaluated the impact of a brief educational
end of the day, will not be a technical or marketing programme on community leaders’ attitudes to and know-
success unless it is accepted by the consumer. Progress in ledge of food irradiation. After viewing a 10-minute video on
the commercial use of irradiation has been slow, mainly food irradiation, those likely to try irradiated food increased
because of misunderstanding. Many from 57% to 83%.
people mistakenly fear, for instance, that
the process may induce radioactivity in An extensive marketing and educational programme was
the food product and that irradiation conducted in South Africa prior to the introduction of
will result in the formation of toxic by- irradiated foods in the market. With regard to irradiated shelf-
products in food. Given these fears, stable meat products, a marketing survey among the general
consumers often find it difficult to evaluate population found that initially 15% of people surveyed
the benefits of this processing technique objectively. indicated they were likely to purchase the irradiated food.
After receiving visual information, those willing to buy in-
creased to 54%. After receiving information and tasting the
Given proper information, will consumers be food, 76% indicated they would purchase the irradiated shelf-
willing to accept irradiated food in a more stable product, while 5% indicated that they probably would
positive light? not buy.

YES. While many consumers are unfamiliar with food irra-

diation, consumer research shows that, as more and more Have many marketing trials been carried out to
factual information is provided, the public increasingly views determine consumer response to irradiated foods?
irradiation in a more positive light. In fact, some studies have
even shown a consumer willingness to pay a premium price Many market tests of irradiated foods have been carried
for irradiated products. Consumers indicate that endorse- out in several countries during the 1980s and 1990s, and

38 / Facts about food irradiation

to date, all have been successful. Market tests and the
ongoing sales of irradiated foods provide the best source
of information on whether irradiated foods meet consumer
needs and wants. They provide excellent information
about consumer acceptance and facilitate the com-
mercialization of irradiation.

USA

Irradiated mangoes sold well in Florida in 1986, and in

March 1987, irradiated Hawaiian papayas outsold their
identically priced non-irradiated counterparts by more than
ten to one. Irradiated apples marketed in Missouri were
also favourably received. In March 1992, a retailer in the
Chicago area featured irradiated strawberries, grapefruit
and juice oranges. The irradiated produce outsold the non-
irradiated produce by ten to one. Irradiated tomatoes,
mushrooms and onions were later marketed with similar
sales success. In the second year of operation and Courtesy of Meat Marketing & Technology Magazine
thereafter, irradiated produce continued to outsell non-
irradiated produce by twenty to one. In 1995 the same poultry captured 60% of the market share when priced
store and several Midwest markets in the USA sold tropical 10% lower than store brand, 39% when priced equally,
fruits, including papaya, litchi and starfruit, from Hawaii in and 30% when priced 10% higher. In 1996 when another
conjunction with a study to determine the potential of test was conducted, the market share increased to 63%
irradiation as a quarantine treatment. As of the end of when the irradiated poultry was priced 10% lower than the
August 1998, the total amount of Hawaiian fruits irradiated store brand, 47% when priced equally, and 18% and 17%
and sold in the USA has been about 280,00 pounds when priced 10% and 20% higher. The irradiated product
demonstrating that consumers are willing to buy these sold better in the more up-market store, capturing 73% of
fruits, and do so repeatedly. In a small scale test of the market when priced 10% lower, 58% when priced
irradiated poultry in Kansas, USA in 1995, irradiated equally, and 31% and 30% when priced 10% and 20%

Facts about food irradiation / 39

 test markets using brown rice, mungbean, and glutinous rice
have been conducted in Indonesia.

Several irradiated foods have been successfully test

marketed in Thailand, including irradiated onions, fragrant
rice and sweet tamarind. Nham, fermented pork sausage
consumed raw in Thailand, is often contaminated with
Salmonella and occasionally with Trichinella spiralis. In
1986, labelled irradiated Nham was sold side by side with
the traditional product. A consumer survey showed that 34%
of the buyers selected irradiated Nham out of curiosity and
Palatability of food treated by irradiation remains unchanged 66% considered it safer from harmful microorganisms.
higher. This is consistent with other attitude surveys and Satisfaction was high, with 95% of customers indicating
market place data that indicate irradiation is more acceptable that they would purchase irradiated Nham again. During the
in up-scale markets. three-month test, irradiated Nham outsold the non-
irradiated product by a ratio of ten to one. This product is
presently available in Thailand on a commercial basis.
Outside the USA
From 1994 to 1996 several irradiated products including dried
Irradiated onions and garlic were first sold in a supermarket mushrooms, dried meat, dried vegetables and dried fish, were
in the Buenos Aires area in 1985. Prior to the first marketing, market tested in the Republic of Korea and found acceptable
consumers were informed about food irradiation in the local to consumers. Irradiated potatoes, onions, and dried fruits
TV, radio and press. Within three days of marketing, the entire were marketed at different times in various shops in
10 tonnes of irradiated product were sold. Subsequent trials Peshawar, Pakistan where consumers found them to be more
gave similar results. acceptable than the non-irradiated products. One tonne each
of onions and potatoes were test marketed at a provincial
Irradiated dried fish and onions have been successfully test fruit and vegetable show in January and February 1991. Thirty-
marketed in Bangladesh. In China, numerous irradiated foods nine per cent of 300 consumers who completed a survey form
have been tested during 1980s and early 1990s including said they were willing to buy irradiated food and to convince
apples, garlic, seasonings, meat products, sweet potato wine, others to buy it, and 57% thought food irradiation should be
potatoes, tomatoes, and dehydrated vegetables. Successful commercialized. Market tests with irradiated onions have

40 / Facts about food irradiation

been carried out in the Philippines since 1985 and sales of
irradiated onions have always been high. When irradiated
onions and potatoes were marketed in two cities in Poland
in 1988, 97% of the consumers responding to a survey
evaluated the products positively, and say they would like to
buy them again.

Irradiated strawberries were test marketed in Lyon, France

in May and June 1987. Two tonnes of products, packed in
covered plastic trays, labelled ‘Protected by Ionization’,
and priced 30% higher than non-irradiated products, sold
well. Market tests have also involved irradiated chicken
Irradiated fresh fruits and vegetables on sale in USA.
breast meat and Camembert cheese.
What kinds of irradiated food items are
In South Africa between 1978 and 1979 irradiated potatoes, currently being marketed at retail level?
mangoes, papayas, and strawberries were sold in 20
supermarkets where they were judged acceptable by 90% of Several irradiated foods are used directly by the food
buyers. Over a six-year period, several popular dishes, for industry. For example irradiated spices and mechanically-
example grilled chicken, curried chicken, bacon, curried beef, deboned poultry meat are used for manufacturing various
and a Malaysian dish called bobotie, were evaluated by a types of processed food. Many irradiated foods are also
large number of groups, including hikers and sea voyagers. being marketed at the retail level.
High acceptance was indicated by researchers. Approximately
200 members of the Defence Force tested the products and
showed overwhelming preference for the irradiated product Fresh Fruits
over freeze-dried and canned counterparts.
Since the first commercial food irradiator in the USA
Thus, all of the marketing trials carried out have clearly de- (operated by FOOD TECHnology Service, Inc., formerly
monstrated that consumers are receptive towards irradiated Vindicator Co.) began operating in Mulberry, near Tampa,
food and will select it in preference to a non-irradiated equi- Florida in 1992, irradiated strawberries, tomatoes and citrus
valent when they perceive benefits. In all of these trials it was fruits have been marketed at several retail outlets in Florida
evident that informed consumers will accept irradiated foods. and Illinois. The USDA issued its policy in 1996 to accept

Facts about food irradiation / 41

irradiation as a quarantine treatment of fresh fruits against marketed at retail levels in Belgium. Irradiated spices,
fruit flies regardless of the host commodities. Fruits from condiments and seasonings are also available in China.
Hawaii including papaya, rambutan, litchis and cherimoya
which are natural hosts of fruit flies have been irradiated
and marketed under a special permission from the USDA at Frog Legs
the retail level in several States in the USA since 1995.
All irradiated products are labelled with the irradiation Because of strict microbiological specifications in France,
logo and a statement ‘treated by irradiation’ either on the most, if not all, frog legs marketed in the country have
package or at the point of sale. The USDA policy has also been treated by irradiation to ensure their hygienic quality.
made it possible for irradiation to be used as a quarantine The product has to be labelled ‘treated by ionization’ and
treatment of fresh fruits from other countries against major can be purchased in most French food markets.
species of fruit flies, regardless of host commodity as long
as the fruit is not a host for other quarantine pests.
Onions, Garlic
In China, irradiated apples have been marketed at the retail
level in Shanghai and other cities since the early 1990s. Vidalia onions have been irradiated in Florida, to prevent
sprouting, and marketed at retail level in Chicago since
1992. Irradiated garlic has been sold in increasing
Spices and Dried Vegetable Seasonings quantities in several cities in China since the early 1990s.
During 1995-98, about 166,000 tonnes of garlic were
Irradiated spices and dried vegetable seasonings have been irradiated and marketed across China. All products are
retail marketed in South Africa over the past 10 years and labelled to indicate the treatment.
the volume is increasing. In fact, irradiation is used so
routinely by the spice trade in South Africa that it would be
difficult to find spices treated by some other means Chicken
(fumigation, heat) in the country. A variety of processed
food (for example, sauces, salad dressings, sandwich Following the approval of the United States Food and Drug
spread) also incorporate irradiated spices and vegetable Administration (FDA) and the quality control programme
seasonings. All irradiated products have to be labelled with for irradiated poultry in 1993, small quantities of irradiated
an irradiation logo plus the word ‘Radurised’. Since 1995, chicken have been offered for sale in some retail outlets
irradiated spices and dried vegetable seasonings have been in Florida, Illinois, Iowa and Kansas with success.

42 / Facts about food irradiation

Consumers in these States are being given the choice to
buy irradiated chicken without pathogens such as
Salmonella for the first time.

Fermented Pork Sausages

Irradiated fermented pork sausages (Nham, a local delicacy

in Thailand, which is almost always consumed raw) treated
for controlling pathogenic microorganisms and parasites,
are gaining popularity since their first market trial in 1986.
During 1997, about 80 tonnes of Nham were irradiated in
Thailand. Increasing quantities of this irradiated product Nham (fermented pork sausage) is commercially irradiated
are being supplied to supermarkets in Bangkok. In and marketed in Thailand.

addition to marketing in Bangkok, the producers have Shelf-stable, ready-to-eat meals are commercially available
developed new markets in the north and northwest of in South Africa. At present, 12 such meals are in existence,
Thailand where Nham is a staple part of the diet. There is including beef curry, beef stroganoff, chicken curry, lasagna
a widespread demand for this irradiated product as the and a Malaysian dish called bobotie. These meals are
risk from infection by Salmonella and Trichinella spiralis labelled as irradiated and have a shelf-life of greater than
has been removed. The irradiation logo and a statement two years, making them ideal for outdoor activities such
indicating irradiation treatment are required on the label. as hiking, camping, yachting, safaris and mountaineering.

Successful market trials of other irradiated foods such as

Other Food Products rice, mungbeans, potatoes and onions in several countries
in recent years will likely lead to further commercialization
Since a semi-commercial irradiator in Chittagong, of irradiated food in the near future. The actual sale of
Bangladesh went into operation in 1993, small quantities irradiated food in the market in several countries has
of irradiated dried fish (for insect control) have been clearly demonstrated that consumers will accept irradiated
available in the market in Chittagong and other cities in food if they have the choice.
Bangladesh, with labelling indicating irradiation treatment.

Facts about food irradiation / 43

World-wide Utilization of Food Irradiation

Countries which apply food irradiation for commercial purposes

Do not yet apply food irradiation

44 / Facts about food irradiation

Further Reading
ACINF (1986). “Report on the Safety and Wholesomeness of Irradiated FDA (1997). “Irradiation in the Production, Processing and Handling of
Foods”. United Kingdom Advisory Committee on Novel and Irradiated Food”. Department of Health and Human Services, United States Food
Foods, HMSO, London. and Drug Administration, December 3, 1997, Volume 62, Number 232,
Pages 64107-64121.
Anon. (1989). “Memorandum of the United Kingdom House of Lords
Select Committee on the European Communities Irradiation of Foodstuffs Giddings, G.G. and Marcotte, M. (1991). Poultry irradiation for
by the United Kingdom Health and Safety Executive”. HMSO, London. hygiene/safety and market life enhancement. Food Reviews International,
Volume 7, Number 3, Pages 259-82.
CAC (1983). “The Microbiological Safety of Irradiated Food”. Codex
Alimentarius Commission, CX/FH/83/9, Rome. Henkel, J. (1998). Irradiation – A safe measure for safer foods. FDA
Consumer, May–June, Pages 12-17.
CAC (1984). “Codex General Standard for Irradiated Foods and
Recommended International Code of Practice for the Operation of IAEA (1985). “Trade Promotion of Irradiated Food”. Report of an ICGFI
Radiation Facilities used for the Treatment of Foods”. Codex Alimentarius Task Force Meeting, IAEA-TECDOC-391. International Atomic Energy
Commission Volume XV, 1st Edition, Food and Agriculture Organization of Agency, Vienna.
the United Nations/World Health Organization, Rome.
IAEA (1988). “Safety Factors Influencing the Acceptance of Food
CAST (1984). “Foodborne Pathogens – Risks and Consequences”. Council Irradiation Technology”. IAEA TECDOC-490, International Atomic Energy
for Agricultural Science and Technology, Task Force Report, Number 122, Agency, Vienna.
September 1994.
IAEA (1989). “Acceptance, Control of and Trade in Irradiated Food”.
CAST (1986). “Ionizing Energy in Food Processing and Pest Control”. Conference Proceedings, Geneva, 12-16 December 1988, STI/PUB/788,
Report No. 109, Council for Agricultural Science and Technology, Ames, International Atomic Energy Agency, Vienna.
Iowa. USA.
IAEA (1993). “Cost-Benefit Aspects of Food Irradiation”. Proceedings of
Chuaqui-Offermans, N. (1989). Food packaging materials and radiation an International Symposium, Aix-en-Provence, France, March 1993,
processing of food: A brief overview. Radiation Physics and Chemistry, STI/PUB/905, International Atomic Energy Agency, Vienna.
Volume 34, Number 6, Pages 1055-1057.
ICGFI (1986). “Handbook for Conducting Feasibility Studies”. Proceedings
Delincée, H. (1998). Detection of food treated with ionizing radiation. of a Workshop on Economic Feasibility of Food Irradiation, International
Trends in Food Science and Technology, Volume 9, Pages 73-82. Consultative Group on Food Irradiation, Vienna.

Diehl, J.F. (1995). “Safety of Irradiated Foods” (Second Edition). Marcel ICGFI (1992) “Radiation Safety of Gamma and Electron Irradiation
Dekker, Inc., New York. Facilities”. Safety Series No. 107, International Atomic Energy Agency,
Vienna.
Diehl, J.F. and Josephson, E.S. (1994). Assessment of wholesomeness of
irradiated foods (A Review). Acta Alimentaria, Volume 23, Part 2, Pages ICGFI (1995). “Training Manual on Food Irradiation for Food Control
195-214. Officials”. International Consultative Group on Food Irradiation Document
16, IAEA.
Farkas, J. (1988). “Irradiation of Dry Food Ingredients”. CRC Press, Inc.,
Boca Raton, Florida.

Facts about food irradiation / 45

ICGFI (1996). “Report of ICGFI Workshop on Implications of GATT Moy, J.H. (1985). “Radiation Disinfestation of Food and Agricultural
Agreements on Trade in Irradiated Food”. International Consultative Products”. Proceedings of an International Conference, Honolulu,
Group on Food Irradiation Document 23. IAEA, Vienna. Hawaii 1983.

ICGFI (1998) “Irradiation and Trade in Food and Agriculture Products ”. McKinnon, R.G. (1988) Safety considerations in the design of gamma
International Consultative Group on Food Irradiation Policy Document, irradiation facilities and the handling of cobalt-60 sources. Radiation
Vienna. Physics and Chemistry, Volume 31, Numbers 4-6, Pages 563-565.

ICGFI (1998). “Safeguarding our Harvests”. International Consultative McMurray, C.H., Stewart, E.M., Gray, R. and Pearce, J. (1996). “Detection
Group on Food Irradiation Policy Document, Vienna. Methods for Irradiated Foods – Current Status”. Proceedings of an
International Meeting on Analytical Detection Methods for Irradiation
ICGFI (1999). “Consumer Attitudes and Market Response to Irradiated Treatment of Foods, Belfast, Northern Ireland, 20-24 June 1994. Published
Food”. International Consultative Group on Food Irradiation Policy by the Royal Society of Chemistry, Cambridge, UK.
Document, Vienna.
Pczczola, D.E. (1992). Irradiated produce reaches Midwest market. Food
ICGFI (1999) “Enhancing Food Safety Through Irradiation”. International Technologies, Volume 45, Number 5, Pages 89-92.
Consultative Group on Food Irradiation Policy Document, Vienna.
Satin, M. (1993). “Food Irradiation – A Guidebook” (First Edition).
ICGFI Home Page on the Internet (1998). <http://www.iaea.org/icgfi> Technomic Publishing Co., Inc., Lancaster, USA.

Johnston, D.E. and Stevenson, M.H. (1990). “Food Irradiation and The Thakur, B.R. and Singh, R.K. (1994). Food irradiation – chemistry and
Chemist”. Royal Society of Chemistry Special Publication Number 86, applications. Food Reviews International, Volume 10, Part 4, Pages 437-
Cambridge, UK. 473.

Josephson, E.S. and Peterson, M.S. (1983). “Preservation of Foods by Urbain, W.M. (1986). “Food Irradiation”. Food Science and Technology –
Ionizing Radiation”. Volumes I and II, CRC Press Inc., Boca Raton, Florida. A Series of Mongographs, Academic Press Inc., (London) Ltd.

Killoran, J.J. (1983). Packaging irradiated food. In: Preservation of Food WHO (1981). “Wholesomeness of Irradiated Food”. Report of a Joint
by Ionizing Radiation, Edited by E.S. Josephson and M S. Peterson, CRC FAO/IAEA WHO Expert Committee, Technical Report Series No. 659, World
Press, Boca Raton, Florida. Health Organization, Geneva.

Marcotte, M. (1995). “What Have We Learned about Consumer WHO (1988). “Food Irradiation. A Technique for Preserving and
Acceptance of Irradiated Foods?” by Nordion International Inc., Canada. Improving the Safety of Food”. World Health Organization, Geneva.

Merritt, C. (1989) “Radiolytic Products – Are They Safe?”. Safety Factors WHO (1994). “Safety and Nutritional Adequacy of Irradiated Food”. World
Influencing the Acceptance of Food Irradiation Technology, IAEA TECDOC- Health Organization, Geneva, Switzerland.
490, Vienna, Austria.
WHO (1997). “Food Irradiation – Sky’s the Limit”. WHO Press Release
Morrison, R. and Roberts, T. (1990). Cost Variables for Food Irradiators in WHO/68, 19 September 1997, World Health Organization Press Office,
Developing Countries. In: Food Irradiation for Developing Countries in Geneva.
Africa, IAEA TECDOC-576.
Wilkinson, V.M. and Gould, G.W. (1996). “Food Irradiation – A Reference
Morrison, R.M., Buzby, J.C. and Lin, C.-T.J. (1997). Irradiating ground beef Guide”. Butterworth-Heinemann, Oxford, UK.
to enhance food safety. Food Review, Volume 20, Pages 33-35.

46 / Facts about food irradiation

 š
The use of irradiation alone as a
preservation technique will not
solve all the problems of post-
harvest food losses, but it can play
an important role in cutting losses
and reducing the dependence on
chemical pesticides.
š

48 / Facts about food irradiation