FOOD IRRADIATION, JAPAN

Gamma-ray response of novel PMMA dosimeter, Radix W

Hiroshi Watanabe, Tatsuya Ichikawa, Keiko Kitagawara, Yoshishige Sato, ...

2008 Volume 43 Issue 1-2 Pages 1-3
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.1

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The influence of irradiation temperature on the PMMA dosimeter, Radix W, was investigated over the temperature range of 9.5°C to 28°C. From the results of dosimetry tests carried out at three gamma facilities over two years, it was concluded that dose in the range of 5kGy to 150kGy could be determined by one calibration curve to within 7.3%. For doses less than 5kGy, the error exceeded 10%.

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Radiation-sensitivities and DNA homology of radiation-resistant Acinetobacter strains isolated from ingredient of animal feeds such as fish meals

Hitoshi Ito

2008 Volume 43 Issue 1-2 Pages 4-7
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.4

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Seven typical strains belonging to genusAcinetobacterwere isolated from fish meals and bone meals. Guanin + cytosine contents of DNA of these strains were ranged to be 41 to 45%. Many taxonomic characteristics of strains of F1, F14, F50, B4 and J5 were similar toA. radioresistensFO-1, and DNA homology values were obtained to be 71 to 92% compared with 100% ofA. radioresistensFO-1. On the contrary, strains of J16 and J22 had similar characteristics withA. calcoaceticusATCC23055 and also each DNA homology values were obtained to be 37% compared withA. radioresistensFO-1. Their D₁₀values of strains F1, F14, F50, B4 and J5 in gamma-rays under air-equilibrium were also obtained to be 0.60 to 1.70 kGy as similar radiation-resistance with 1.70 kGy of A. radioresistensFO-1. However, D₁₀values of J16 and J22 were obtained to be 0.35 kGy as similar to 0.12 kGy of A. calcoaceticusATCC23055.

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Effect of gamma-irradiation to the embryos growth of kenaf and roselle

Matsuzaka Teruki, Naoki Okuyama, Fujino Hideki

2008 Volume 43 Issue 1-2 Pages 8-13
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.8

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Kenaf and roselle are widely cultivated in many countries and it has been used to produce several products or beverages. Also, these plants are recognized as an environmental friendly crop. The gamma-ray irradiation was commonly used to avoid the spoilage of several vegetables or to inhibit the emergence of larvae from seeds. Recently, radiation breeding was characterized for the creation of new varieties and the improvement of vegetative propagation. As of today, little studies have been reported regarding the radiation sensitivity of these plants. To gain a better understanding on the embryos growth of kenaf and roselle, gamma-ray irradiation was performed on these seeds using 60Co irradiator. A statistically significant difference was observed on germination and embryo growth at irradiated kenaf seeds between control groups. In case of roselle, there was not statistically significant difference in the germination of irradiated seeds between control groups at the same doses. Moreover, the several truncated DNA forms were detected at the irradiated seeds and their embryos in electrophoresis assay. Based on these results, inhibitory effect on germination and embryo growth were closely related to the DNA damages. The present study demonstrates that remarkable difference on the radiation tolerance of seed was found between kenaf and roselle.

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ESR detection of black pepper using standard addition method

Satoko Ogawa, Youko Kaeda, Hiromi Kameya, Hideo Nakamura, Mitsuko Ukai

2008 Volume 43 Issue 1-2 Pages 14-18
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.14

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ESR techniques for studying the detection of radicals induced in gamma ray irradiated pepper were studied. The representative ESR spectrum of the pepper composed of a sextet centered at g= 2.0, a singlet at the same g-value and a singlet at g= 4.0. This reflects the evidence of three independent radicals in the pepper before irradiation. Upon gamma ray irradiation, a new pair of signals appeared. Using standard addition method for solid sample technique we prepared the experimental samples containing 2.0-20.0 w/w % irradiated black pepper. The progressive saturation behavior (PSB) at various microwave power levels indicated quite different relaxation behaviors of those signals. For the evaluation of radiation-induced radicals and irradiation effects we proposed a new protocol using the standard addition method. This would be called an advanced protocol for the detection of irradiated black pepper.

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Detection of irradiated foods with the photo-stimulated luminescence technique

Selection of a glass fiber filter for evaluating the performance of the PSL detectors

Masayuki Sekiguchi, Masao Yamazaki, Michiko Goto

2008 Volume 43 Issue 1-2 Pages 19-24
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.19

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The PSL method is useful as a screening technique of irradiated foods to support efficient uses of TL analysis. Recently, there has been the growing need for the system check or calibration using the standard materials with spread of domestically-produced PSL detector. In this research, we characterized the PSL of several types of glass fiber filters and compared the cumulate photon counts of a selected filter of them (GA-100) with those of the SUERC paprika standard for PSL measurements. GA-100 filter showed a linear relationship between cumulate photon counts and irradiation doses, and the cumulate photon counts in the first 2 months after gamma rays irradiation (261Gy) were markedly decreased and reduced to about 5000 counts (the upper threshold of PSL) after 4 months. However, further long-term storage and dose increase was necessary to produce the filters with more adequate PSL property as a standardmaterial. Light exposure (630Lux) within 3 minutes to GA-100 had little effect on the cumulate photon counts. GA-100 showed relatively less variation in cumulate photon counts compared with the paprika standard in a series of studies.

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TL glow ratios at different temperature intervals of integration in thermoluminescence method

Comparison of Japanese standard (MHLW notified) method with CEN standard methods

Setsuko Todoriki, Kimie Saito, Yuka Tsujimoto

2008 Volume 43 Issue 1-2 Pages 25-36
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.25

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The effect of the integration temperature intervals of TL intensities on the TL glow ratio was examined in comparison of the notified method of the Ministry of Health, Labour and Welfare (MHLW method) with EN1788. Two kinds of un-irradiated geological standard rock and three kinds of spices (black pepper, turmeric, and oregano) irradiated at 0.3kGy or 1.0kGy were subjected to TL analysis. Although the TL glow ratio exceeded 0.1 in the andesite according to the calculation of the MHLW notified method (integration interval; 70-490 °C), the maximum of the first glow were observed at 300°C or more, attributed the influence of the natural radioactivity and distinguished from food irradiation. When the the integration interval was set to 166-227°C according to EN1788, the TL glow ratios became remarkably smaller than 0.1, and the evaluation of the un-irradiated sample became more clear. For spices, the TL glow ratios by the MHLW notified method fell below 0.1 in un-irradiated samples and exceeded 0.1 in irradiated ones. Moreover, Glowl maximum temperatures of the irradiated samples were observed at the range of 168-196°C, and those of un-irradiated samples were 258°C or more. Therefore, all samples were correctly judged by the criteria of the MHLW method. However, based on the temperature range of integration defined by EN1788, the TL glow ratio of unirradiatedsamples remarkably became small compared with that of the MHLW method, and the discrimination of the irradiated sample from non-irradiation sample became clearer.

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Analysis of 2-alkylcyclobutanone and detection of the irradiated food

Hirotaka Obana

2008 Volume 43 Issue 1-2 Pages 37-45
Published: September 30, 2008
Released on J-STAGE: February 25, 2011

DOIhttps://doi.org/10.5986/jrafi.43.37

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Quantity and Economic Scale of Food irradiation in the world

Tamikazu Kume

2008 Volume 43 Issue 1-2 Pages 46-54
Published: September 30, 2008
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.43.46

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