Risalah Seminar Nasional Pengawetan Makanan Dengan Iradiasi, Jakarta, 6 - 8 Juni 1983

FOOD IRRADIATION DEVELOPMENT IN JAPAN

Toshiharu Kawabata *

ABSTRAK - ABSTRACT

Perkembangan iradiasi bahan pangan di Jepang. Penelitian iradiasi bahan pangan yang per­tama di Jepang dilakukan untuk mengawetkan ikan dan hasil-hasil perikanan. Tahun 1966,Komisi Tenaga Atom Jepang (JAEC) membentuk Proyek Nasional Iradiasi Bahan Pangan, danpada tahun 1967 Panitia Pengarah dalam penelitian radiasi pangan di Biro Tenaga Atom, BadanIlmu Pengetahuan dan Teknologi memilih jenis-jenis bahan pangan berikut yang mempunyainilai ekonomi penting bagi negara yaitu kentang, bawang Bombay, beras, gandum, sosis, kama­boko dan jeruk untuk dipelajari. Proyek nasional tersebut diharapkan selesai pada akhir tahunfiskal 1981. Berdasarkan hasil studi proyek tersebut, kentang iradiasi diperbolehkan untuk kon­sumsi manusia tanpa syarat dalam tahun 1972. Tahun 1973, sebuah iradiator komersial untukkentang didirikan di Shihoro, Hokkaido. Tahun 1980, Panitia pengarah menyerahkan laporanakhir study tentang keampuhan dan keamanan bawang Bombay iradiasi kepada JAEC. Makalahini memberikan penjelasan singkat tentang aspek hukum makanan iradiasi di Jepang, dan status

penelitian keamanan dari 7 jenis "}akanan iradiasi yang diselidiki. Di sam ping itu, diuraikan pulasecara singkat tentang topik penelitian iradiasi kamaboko, khususnya tentang keampuhannyadan cara baru untuk mendeteksi perlakuan iradiasi pada produk.

Food irradiation development in Japan. In Japan, the first food irradiation research wascarried out on the preservation of fish and fishery products. In 1966, the Atomic Energy Com­mission of the Japanese Government (JAEC) decided the promote the National Project onFood Irradiation and, in 1967, the Steering Committee on food irradiation research in theAtomic Energy Bureau, S.cience and Technology Agency, selected the following food items asof economic importance to the country, i.e., potatoes, onions, rice, wheat, Vienna sausage, ka­maboko (fish meat jelly products) and mandarin oranges. The National Project is expected tofinish at the end of the 1981 fiscal year. Based on the studies by the National Project, irradiatedpotat,.oes were given "unconditional acceptance" for human consumption in 1972. Already in1973, a commerci.al potato irradiator was built at Shihoro, Hokkaido. In 1980, the SteeringCommittee submitted a final report on ,the effectiveness and wholesomeness studies on irra­diated onions !,o the JAEC. This paper gives a brief explanation of the legal aspects of food irra­diation in Japan, and the present status of wholesomeness studies on the seven items of irra­diated food. In addition, topics concerning food irradiation research on kamaboko, especiallyon the effectiveness and" a' new detecting method for the irradiation treatment 'of these pro- .ducts, are outlined.

INTRODUCTION

In Japan, the first food irradiation research was carried out on the preservationof fish and fish products at the Tokyo University of Fisheries in 1945. In 1955, theNational Food Research Institute started studies on radiation treatment of agricul­

tural products. In the following year, 1956, studies on the preservation of fish andfish products by radiation were started at the Tokai Regional Fisheries Research la­boratory, Tokyo. At that time, however, facilities and instruments for food irradia­tion research in Japan were very poor. During 1957-1958, irradiators, each with a1000 Ci 60Co source, were built at the Tokyo University of Fisheries, Tokai Re­

gional Fisheries Research Laboratory and Institute of Physical and Chemical Re-search.

Department of Biomedical Research on Food, National Institute of Health, Tokyo, Japan.

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In accordance with the progress in research and the increase in numbers offood irradiation researchers, the Research Association for Food Irradiation was or­

ganized in 1964 by researchers working in the Kanto district. The following year,this organization expanded on a nation-wide scale to form the Japan Research Asso­ciation for Food Irradiation (JRAFI). At almost the same time, the Japan Atomic

Energy Commission (JAEC) set up the Food Irradiation Advisory Group to investi­gate and, deliberate on the matters concerning the food irradiation program in Ja­pan, and in 1966 the Commission issued the Fundamental Program on Food Irra­diation Research and Development.

According to an established policy, the Science and Technology Agency hasdecided to put the National Project on Food Irradiation Research in operationunder the Special Research Fund for Food Irradiation Research and Development.

In 1967, the Steering Committee on Food Irradiation Research in the AtomicEnergy Bureau, Science and Technology Agency, selected the following seven fooditems of economic importance to the country: potatoes, onions, rice, wheat,Vienna sausage, "kamaboko" (fish meat jelly products) and mandarin oranges.

At first, the National Project was scheduled to be fmished in 1974, however,owing to the delay in the schedule for carrying out toxicological studies, and newadditional' mutagenic studies on irradiated foods, the National Project has been ex­tended until the end of the 1982 fiscal year.

In 1970, the Food Irradiation Research and Development Laboratory was es­tablished in the Takasaki Radiation Chemistry Research Establishment (TRCRE)

of the Japan Atomic Energy Research Institute, and in 1973 a gamma irradiatorwith a 100 kCi 60Co source and a laboratory were constructed there. In 1974, thetotal 60Co source activity was increased to 200 kCi. Since then much work hasbeen done on the radiation technology, especially on large-scale irradiation techni­

ques for various food items. At the TRCRE laboratory, the development of large­scale irradiation techniques, especially for packed "kamaboko" and Vienna sau­sages, has been carried out using the linear-motion two-pass-type conveyer of thefood irradiation facilities. Dosimetry was performed for the conveyer system whichwas installed at the accelerator of the Osaka Prefectural Central Institute for Radia­tion Research for the irradiation treatment of mandarin oranges specimens forwholesomeness studies.

Research activities, carried out by various national institutes and universities

since 1967 up to 1982, are shown in Table 1.In this paper, a brief explanation is given on several topics concerning food

irradiation research and development in Japan.

NA nONAL PROJECT ON FOOD IRRADIA nON RESEARCH

The Project on Food Irradiation Rese!lrch on the selected seven food items,potatoes, onions, rice, wheat, Vienna sausages, "kamaboko" and mandarin orangeswas terminated on March 1983 after 15 years of extensive studies.

Based on the scientific data, potato irradiation was given "unconditional accep­tance" for human consumption in 1972, and the treatment was already commer­cialized since 1973 at Shihoro Agricultural Cooperative, Shihoro, Hokkaido, Japan.

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(The present status of potato irradiation will be described more in detail afteIWard).

Toxicological studies on seven food items including mutagenic tests conducted

at the National Institute of Hygienic Sciences have been completed. To date, no

harmful effect has been observed in the toxicological studies on irradiated foods.

The report on onion irradiation was evaluated and authorized by the Japan

Atomic Energy Commission in 1982, and the treatment is waiting to be presented

to the Ministry of Agriculture, Forestry and Fisheries for consideration. If agreed,

it will be sent to the Ministry of Health and Welfare for approval.

At present, draft reports on radiation disinfestation of rice and wheat are being

prepared by a working group under the Steering Committee on Food Irradiation

Research, and will be completed shortly. The draft reports will be presented to the

Steering Committee for review and confirmation, then these will be approved as the

final reports to be presented to the J AEC, then, these will be declassified after ap­

proval by JAEC.

Draft reports on "kamaboko" and Vienna sausages from the participating insti­

tutions are now requested to be presented to the Science and Technology Agency.

ON "KAMABOKO" IRRADIATION

In Japan, fish and sheIIfish are the most important animal protein sources, and

the total fish catch exceeds II million tons annuaIIy. Among various fish products,

"kamaboko" and related fish-paste products are traditional foods and the annual

production of these products is approximately one million tons, which is equivalent

to the consumption of about one-third of the total fish catch. "Kamaboko" is fairly

perishable food, and since ancient times this food has been regarded as one of the

most important sources of various food poisonings such as those from Salmonellaand Staphylococcus. The purpose of radiation treatment of "kamaboko" is prima­

rily radurization to prolong the shelf-life, but it would also be effective for elimi­

nating non-spore formers such as Salmonella, Staphylococcus and Vibrio parahae­molyticus, though the radiation dose is rather low.

Most of the work on "kamaboko" irradiation has been carried out by SASA­

Y AMA and his coIIeagues (14) at the Tokai Regional Fisheries Research Labora­

tory, Tokyo. Here is a brief summary of SASA Y AMA'S work.

Table 2 iI1dicates the organoleptic tests of irradiated "kamaboko" conducted

immediately after treatment with varying doses of gamma radiation. As can be seen,

no detectable change in color, flavor and odor was observed in the "kamaboko"

treated with doses below 300 krad (3 kGy), while slight but apparent irradiation

odor and color change could be detected when these products were irradiated withdoses over 400 krad.

As shown in Table 3 (1), the shelf-life of irradiated "kamaboko" treated witha 300 krad dose and stored at 12-15°C was found to be about two weeks, while

the unirradiated control decomposed within a few days.

Table 4 indicates the effect of irradiation (a 300-krad dose) on the physical

properties directly relating to the quality of "kamaboko", such as elasticity, break­

ing strain and softness. It is general1y recognized that the elasticity is the most im·

15

portant index for evaluating the quality of "kamaboko", and the higher the elasti­city of a product, the better the quality. It is interesting that the elasticity of anirradiated "kamaboko" has been found to be higher than that of the unirradiatedcontrol, and the difference in the elasticity between the irradiated "kamaboko" and

the control became more conspicuous with the lapse of time.As shown in Table 5 (2), the whiteness of "kamaboko" became more intensive

when it had been treated with a 300 krad dose. It is also to be noted that the white­

ness of the surface layer of a product was much more intensive than that of theinner part.

These results shown in Tables 4 and 5 indicate that the irradiation treatment of

"kamaboko" has the advantage of improving the product quality.Figure 1 (3) illustrated the effect of radiation of the extension of shelf-life of

"kamaboko" packed in plastic casing. Almost no marked difference was observed inthe shelf-life of both irradiated groups (either air-packed or vacuum-packed) andunirradiated control (either air-packed or vacuum-packed), when these productswere stored at 28-30°C. By contrast, when these products were stored at 9-11 °cthe irradiated vacuumpacked "kamaboko" exhibited the longest shelf-life - morethan 40 days - followed by the irradiated air-packed "kamaboko" with a shelf-lifeof about 25 days. But the shelf-life of unirradiated controls both air-packed andvacuum-packed was found to be less than 14 days.

NEW METHOD FOR THE DETECTION OF IRRADIATED "KAMABOKO"

As far as we know, no appropriate method is available for detecting whether afood has been treated with lower doses of ionizing radiation. Recently, TSUCHIDAof our laboratory developed a new simple technique for detecting irradiated "kama­boko" (5). The principle of her method is based on the detection of fluorescencein the irradiated "kamaboko" using an ultraviolet (UV) light of 350 nm.

As a second step, she studied the mechanism for emitting the fluorescence ofirradiated "Kamaboko". When the excitation spectra on the cut-surface of "kama­boko" on the second day after irradiation were determined at a fix emission wavelength of 420 nm, using a fluorescence spectrometer, a marked difference could bedetected in the absorption peaks between irradiated materials and unirradiatedcontrol, Le. three peaks appeared at 300, 325 and 350 nm, and it was noted thatthe 325-nm peak can be seen only in the irradiated "kamaboko".

When the fluorescence excitation and emission spectra of irradiated "kama­boko" were determined after 22 days of storage after irradiation, it was found thata characteristic absorption maximum at 325 nm still apparently remained, while thepeaks at 300 and 350 nm were observed both in the irradiated and in the control

materials. Then, TSUCHIDA tried to extract the fluorescent substance(s) with H20and chloroform-methanol mixture according to the FOLCH method. She foundthat the fluorescent substance(s) can be extracted only by the FOLCH method. Itwas also found that these fluorescence excitation and emission spectra were iden­tical with those observed in the cut-surface of the irradiated "kamaboko".

Because of the extremely low concentration of the fluorescent substance(s)in the irradiated "kamaboko", TSUCHIDA has tried experiments in a model sys-

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tern, and found an interesting phenomenon. Arachidonic acid is known to be wide­ly distributed in various fish oils, and it has 20 carbon atoms with four doublebonds in the molecule. TSUCHIDA employed methyl arachidonate as a test mate-

. rial. The intact (unirradiated) form of this compound never gave any wavelengthof flourescence, while after treatment with gamma radiation this compound wasconverted into a flourescent substance to give a quite identical fluorescence exci­tation and emission spectra from the irradiated ''kamaboko''. More recently, shefound that the change in the fluorescence spectra was caused by the formation ofa conjugated tetraena from the 2 diene moiety in an unsaturated fatty acid such asarachidonic acid in "kamaboko".

Concerning the toxicity of the fluorescent substance formed in irradiated"kamaboko", a toxicity test of both fluorescent substances, one of which was thechloroform extract from the irradiated "kamaboko", and the other, the irradiatedauthentic methyl arachidonate, was conducted by using the chick embryo inocula­tion technique. No appreciable difference in the toxicity was detected among theextracts from irradiated and unirradiated ''kamaboko'', and the irradiated and un­irradiated methyl arachidonate.

PRESENT STATUS OF COMMERCIAL IRRADIATION OF POTATOES

Based on the studies by the National Project on Food Irradiation Research, theirradiation treatment of potatoes at a maximum average dose of 0.15 kGy was given"unconditional acceptance" for human consumption by the Minister of Health andWelfare in conformity with the Japanese Food Sanitation Law in 1972. In thefollowing year, the Shihoro Agricultural Cooperative, Shihoro, Hokkaido, built acommercial irradiator having a 60Co source of 300 kCi initially which is capable of

treating about 350 tons of potatoes per day for a period of 3 months in a year,thereby the irradiation capacity of this facility exceeded 30,000 tons of potatoesper year. This plant costed a total of about 1.3 million US dollars. Since 1974, anaverage of approximately 15,000 tons of potatoes has been irradiated annually.More recently, the treating amounts of potatoes tend to increase, and about 80% ofirradiated potatoes are being consumed for the preparation of products such as po­tato chips, frozen French fried potatoes, etc.

In Japan, the annual output of potatoes is about 3.5 million tons, and the percapita consumption is about 32 kg, which is as low as 1/3 to 1/8 those of Westerncountries such as United States, United Kingdom, France, and West Germany.

Concerning the domestic potato distribution system, Japan has following twospecial features: the 1st feature is that no chemical sprout inhibitor like maleichydrazide (MH) has never been permitted to use for sprout inhibition of tubers andbulbs, and the 2nd one was the absence of large scale potato processing industrieswhich have their own potato distribution system until several years. These two rea­sons and the' Government subsidies for stabilizing the supply and market price ofpotatoes have accelerated the commercialization of potato irradiation in Japan.

Japanese experience in establishing the 1st commercial potato irradiation plantwould be useful to the countries who have a domestic potato distribution systemsimilar to that of Japan, especially in the Asian and Pacific regional countries.

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Pla. h illumnt~~ tho Dri~~ nuetu~tion of Dotllto~i in ID~TOKYOCcntrID WhoIG'

sale Market (6). Ip the past, the price of potatoes tended to rise in the off-season,from February to March. In order to prevent price fluctuation of potatoes, theVegetable Price Stabilization Fund (VPSF) of Japanese Government, and the To­kyo Metropolitan Government used to purchase several thousand tons of potatoesto stabilize their price in the off-season. This countermeasure was successful in over­coming the price fluctuation till February, however, it became fairly difficult toprevent rising the price of potatoes during March and April because in these seasonpotatoes start sprouting. As can be seen in Fig 6, the price of potatoes in the TokyoCentral Wholesale Market has been apparently stabilized throughout a year afterthe potato irradiation was commercialized in 1974. It is to be noted that purchasingof only 4,000 to 5,000 tons of irradiated potatoes by the VPSF resulted in successin controlling the price fluctuation of potatoes in 1975/1976, although an averageof 12,000 tons of potatoes arrive at the Tokyo Central Wholesale Market everymonth.

In 1977, we met with a large scale boycott movement against irradiated po­tatoes by a minor activist group of consumers in Japan, and I should like to give anoutline of this incidence. This movement initiated when a consumer group con­sisted of radical activists published a series of feature articles during August 1976and February 1977 about the danger of irradiated foods. In February 1977, the ra­dical groups informed to the press that they will launch a boycott movement aga­inst irradiated potatoes. The press started to write sensational articles about ques·tionable safety of irradiated potatoes almost every day. In March 1977, the Ja­panese Research Association for Food Irradiation (JRAFI) summed up all availableinformation to oppose the position of the consumer's groups, and started to copewith the press by providing interpretation of safety of irradiated potatoes. It wasdifficult, however, to conveh gen.eral public misunderstanding immediately. In ad­dition, on 29 March, 1977, a congressman belonging to an opposition party sub­

mitted a 15 item-questionn~~e entitled "Questions on Irradiate.d Foods" to thePresident of House of Representatives. Several governmental agencies concerning inthis problem jointly prepared .the official reply to the questionnaire on April 5.Taking this opportunity, Government authorities started to take efficient measuresto the press to tranquilize irrational consumer's movement. The JRAFI edited aspecial feature issue of its Journal "Food Irradiation Japan", Vol. 12, No.2 inwhich all the documents related to the boycott movement were collected, andthoroughly analyzed. The special issue was circulated to concerned organizations,and the publication was a great success to overcome general misunderstanding andto promote better understanding on the wholesomeness of irradiated foods. At thebegining of 1978, the boycott movement completely stopped, then, the marketingof irradiated potatoes gradually increased mostly for processing purpose.

REFEREN CES

1. SASAYAMA, S., Irradiation preservation of fish meat jelly product I. Effect of low-doseirradiation and storage on acceptability of "Kamaboko", Bull. Tokai Reg. Fish. Res. Lab.70(1972)57.

18

2. SASAYAMA, S., Irradiation preservation of fish meat jelly products II. Classification ofspoilage bacteria in irradiated "Kamaboko", Bull. Tokai. Reg. Fish. Res. Lab. 75/(1973)39.

3. SASAYAMA, S., SHIBA, M., and YAMAMOTO, T., Irradiation preservation offish meatjelly products III. Irradiation effect on "Kamaboko" packed with plastic casing, Bull.Tokai. Reg. Fish. Res. Lab. 82 (1975) 97.

4. SASAYAMA, S., Irradiation preservation of fish meat jelly products IV. Irradiation effecton fried ':Kamaboko" (age-kamaboko), Bull. Tokai. Reg. Fish. Res. Lab. 87 (1976) 25.

5. TSUCHIDA, M., and AIBARA, K., On the detection of irradiated food, with special refe­rence to irradiated "Kamaboko", Radiation and Industries No. 20 (1982) 23. Text in1apanese.

6. UMEDA, K., The commercial experience of Shihoro irradiator, September 17 (1979) 1.

Table 1. Researches conducted by the National Project on Food Irradiation(1967 to 1982)

1. Effectiveness of irradiation and irradiation technology

2. Wholesomeness studies (Nat. Inst. Hyg. ScL)

(1) Toxicological studiesAcute toxicity (monkey)Chronic toxicity (mice & rats)Reproduction (mice, for 4 generations)Teratogenicity (mice, dominant-lethal test)Mutagenicity

bacteria, mammalian cells(2) Nutritional studies (Nat. Inst. Nutr.)

(3) Microbiological studies (Nat. Inst. Health)

(4) Detection techniques of irradiated food (Nat. Inst. Health)

3. Basic research

(Inst. Phys. Chern. Res.)(Several national universities)

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NoTable 2. Organoleptic tests of "kamaboko" conducted immediately after irradiation.

Dose

(krad)

Color

Air-packed Vacuum-packed

Texture:

Air-packed Vacuum-packed

Odor:

Air-packed Vacuum-packed.-

200 NormalaNormalaNormalaNormalaNormalaNormala

300

" """"400

" """?

500

" """Slight jrrad.Slight irrad.

odourodour

700

YellowishNormalSlightly hardenedSlightly hardenedApparent irrad.Apparent irrad.odour

odour

a No appreciable difference was observed between irradiated and unirradiated control.

Table 3. Change in the quality of "kamaboko" during storage at 12-15°C.

Sampleo

Storage period (weeks)2 3 4

Irradiated Normal

(300 krad) (O/IO)a

Normal

(0/10)

Normal

(0/10)Slimy SlimyPartial Partial

mould growth mould growth(3/10) (6/10)

-------------------------------------------------

Unirrad. NormalDotted slimeSlimySlimy(control)

PartialSurfacemould growth

coveredwith mould(0/10)

(10/10)(10/10)(10/10) Decomposed

(10/10)

aFigures in parentheses: No. of deteriorated/No. of test samples.

Table 4. Effect of irradiation (300 krad) on the physical properties relating to thequality of "kamaboko"

Days of Elasticity: aBreaking strain: bSoftness:cstorage (12-15°C) Irrad.

Unirrad.Irrad.Unirrad.Itrad.Unirrad.

0

465 g450 g28mm29mm130°130°

7

4704582625lZ5128

14

660580323211~120

28

7435903633116122

a, b, c

Measured by the Okada gelometer.

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- -- -- ------------

Table 5. Effect of irradiation (300 krad) on the whitenessa of "kamaboko".-Days of

SurfaceSurface

storage (12-15°C)Irrad.Unirrad.Irrad.Unirrad.

0

44.4%40.8%44.3%41.5%

7

44.638.343.741.3

14

43.741.644.543.6

28

42.939.344.442.6

a The whiteness of "kamaboko" was measured by a Ranter's chromaticity meter.The whiteness of the standard plate was 78.0%.

22

A

v

A

v

9-110

A - - AIR-PACKED

V - - VACUUM-PACKED

• NON-IRRADIATED

o IRRADIATED, 300krad

o 10 20 30 40

SHELF LIFE, DAYS

50

Fig. 1. Extension of the shelf-life of "age-kamaboko" by radiation treatment.The shelf-life was determined on the 5-point hedonic scale for appearance,texture, odor and taste.

100

o250

Em : 420 nm

300 350 400

Wave length (nm)

Ex: 350 nm

450 500

Fig. 2. Fluorescencespectra on the surface ofirr:ldialed "kamaboko".(TSUCHIDA et aI., 1982).

23

100 Em : 504 nm Ex : 360 nm

0"200

A /I V / ',\{.'01/. ", ~ / .\~"'~""'I' "~

300 400 SOO . 400· 500

Wave length (nm)

600 700

Fig. 3. Fluorescence spectra of the saline solution and methanol soluble fractions ofirradiated "kamaboko".

(TSUCHIDA et aI., 1982).

50

<l>U~<l>U'"<l>•...

g 254::

.~.•..C\j

~

250 300 350 400 450

Wave length (nm)

300 krad

500 550

Fig. 4. Fluorescence spectra of the chloroform extract from the irradiated "kama­boko" .

(TSUCHIDA et aI., 1982).

24

50

, ,

250 300 350 400 450Wave length (nm)

·'500 550

Fig. 5. Identifjcation of the fluorescent substance(s) in the irradiated "kamaboko".(TSUCHIDA et aI., 1982)

Off season

150

I::.Q.•..0:1

B 100u;::S

G:

50

Boycott confusion

U17'

74/7S

76/77

9 10 II 12 I 2 3 J. 5...-:---. Hokkaido potato ----..

678(month)

*

Fig. 6. Price fluctuation of potatoes in Tokyo wholesale market.74/75,75/76: vegetable price stabilization fund controlled the wholesale

price by irradiated potatoes.

average price of each season is indicate as 100.

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DlSKUSI

LAKSMI SISWOPUTRANTO:

Would you like to explain us what's the feeling/opinion of most Japanese peopleif they will consume irradiated food. I am inclined to asume that many people willstill have negative prejudice to irradiated food. Especially foods that are usually tobe consumed in raw or fresh condition like fruits and vegetables. I am afraid thatsuch food have more dangerous aspect than other food usually consumed after

being cooked like fish, potatoes, etc.

T. KAWABATA :

As you know, Japanese people are fairly sensitive to nuclear weapons, and some­times they are called to be "nuclear allergy", so, many people are concerning aboutthe harmful effects causative even from the peaceful use of radiation, and someactive consumergroups opposed the use of food irradiation treatment. This ten­dency might be attributable to the short of exact scientific knowledge. To solve thisproblem, much more effort should be paid to the consumer education.

NAZIR ABDULLAH:

Could you tell us about the wholesomeness studies carried out on rice in your coun­try? And what are the result obtained? What about rice, is it already "cleared" forhuman consumption?

T. KAWABATA.

The toxicological data on irradiated rice clearly indicate no harmful effect whentested on various experimental animals. This means that irradiated rice is whole­some for human consumption. At the present time, no clearance for rice irradiationhas been given by Japanese Government, because the final report from the JapanAtomic Energy Commission has not yet been presented to the Minister of Health &Welfare.

M. RIDWAN:

You do a lot of research in food irradiation but Japanese Government cleared onlypotato. Is the delay in clearing of these food items mainly due to scientific pro­blems or economic point of view?

T. KAWABATA:

Concerning the commercialization of an irradiated food item, there are several fac­tors, especially those relating to the technical and economic feasibilities are themost important. In addition, public acceptance might be the most important factor.As to the commercialization of "kamaboko" and Vienna sausages, the necessity ofirradiation treatment has been changed, mostly from the economical point of view,especially the development of low temperature transportation system has affectedseriously on the necessity of food irradiation.

MUNSIAH MAHA :

As you just explained, a lot of works have been done in Japan in all aspects of food

26.

irradiation, not only in technical aspect, but also on wholesomeness test. And no

negative effect was found in the irradiated food. However, to date only potatoes isallowed to be irradiated for human consumption. What is the reason, and is thereany trend now in Japan to get more clearances for irradiated food items? I am ask­

ing this, because Japan is one of our important market, especially for fishery pro­ducts. And our government is very careful to approve irradiated food because wedon't want to destroy our foreign market by using this technology. Since Japan hasspent a lot of money to develop this technology , not only in Japan but also forsupporting activities in this field in other countries (South East Asian Countries),could you and other Japanese scientists force your government to give more cle­arances.

T.KAWABATA:

Concerning the clearance of irradiated food, I am more a scientist, and I don't

think I am in the best position to answer. However, I hope these clearances wouldbe given from the Ministry of Health & Welfare of Japan after receiving the finalreport to be presented from the Japan Atomic Energy Commission.

C.J. SOEGIARTO :

1 get the impression that the Japanese Government/people is reluctant to consumeirradiated fish.)apan obtained its fish from international or foreign countries water.What is the degree of bacterial contamination in fishes and marine products youcatch in these waters or buy from foreign exporters.

T. KAWABATA:

The average total fish catch in Japan is about 11 million tons annually, and we im­port about 2 million tons of a variety of fish and shellfish from foreign countries.Among those imported commodities, frozen shellfish especially frozen shrimps andprawns are most important, and the total amounts of imported shrimps and prawnsreach about 150.000 tons, and the price of these is about 10-15 million US dollars.We don't have bacterial standards for these frozen fish and shellfish, but we havestandards for frozen food such as beheaded shrimp. Therefore Japanese frozen foodindustry are concerning about the bacterial contamination of imported fish andshellfish.

INDONESIAN CONSUMER ORGANIZATION:

1. How is the reaction of the consumer when the first irradiated food go public inyour country and what is the impact of it.

2. How can the consumer know that the product has been irradiated if the labelon it is not complete.

3. How does your country control irradiated food to avoid high irradiation thatcan be dangerous to consumers (Marketing Test).

T. KAWABATA:

1. In 1972, irradiation or potatoes was permitted by the Government. In the fol­lowing year the commercial irradiator was constructed at Shihoro, and in

March 1974, the first batch of irradiated potatoes entered in the TOkyo Central

27

Wholesale Market. However, ahnost no objection has been reported among con·sumers.

2. According to the Food Sanitation Law, irradiation label is shown on the con­tainer, but not on individual potato itself.

3. Under the Food Sanitation factory should keep a food sanitation controller tosecure an accurate irradiation treatment. Also, the measure for determiningirradiation dose is standardized by the law (Fricke type of Dosimeter).

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