FOOD IRRADIATION, JAPAN
Online ISSN : 1884-3611
Print ISSN : 0387-1975
ISSN-L : 0387-1975
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Volume 34, Issue 1-2
Displaying 1-7 of 7 articles from this issue
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  • New LASER Fluorometric HPLC Detection for ortho-Tyrosine in Gamma-Irradiated Phenylalanine Solution and Pork
    Makoto Miyahara, Taeko Nagasawa, Keiko Izumi, Mayumi Kitamura, Masatak ...
    1999 Volume 34 Issue 1-2 Pages 3-8
    Published: September 30, 1999
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.5986/jrafi.34.3
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    New analytical procedure for o-tyrosine was studied to investigate effects of gamma irradiation on aqueous phenylalanine solution and pork. The process includes extraction and hydrolysis of protein, derivatization of the free amino acid by fluororeagent, and finally separation and detection by LASER fluorometric HPLC. The detection limit was 25 ng.
    To study how the procedure works, irradiated phenylalanine solution and pork were analyzed. The samples were irradiated at doses up to 10kGy at room temperature.
    Three tyrosine isomers were detected in phenylalanine solution, and 2 isomers (o-and p-tyrosine) were found in pork. Dose response was found in the formation of the isomers both in phenylalanine solution and in pork. O-tyrosine peak obtained from irradiated pork was separated from interference successfully. Those findings illustrate the procedure may be applicable to detection of irradiated food.
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  • DNA comet assay for rice seeds treated with low energy electrons (“soft-electrons”).
    Setsuko Todoriki, Toru Hayashi
    1999 Volume 34 Issue 1-2 Pages 9-15
    Published: September 30, 1999
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.5986/jrafi.34.9
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    As rice seeds are sometimes contaminated with phytopathogenic organisms such as blast disease fungi and nematodes, a novel non-chemical disinfection method for rice seeds is highly required. In order to develop a disinfection method, the effect of low energy electron (“soft-electrons”) on seed DNA was examined by using the neutral comet assay. Rice seeds (whole grain) were treated with electrons of different acceleration voltages (180kV to 1MV) at a dose of 5kGy. Nucleus suspensions were prepared from whole brown rice and subjected to electrophoresis. DNA from un-irradiated (control) seeds relaxed and produced comets with a short tail, most of the comets distributed within the range of comet length between 30μm to 70μm. In the case of seeds treated with electrons at acceleration voltages up to 190kV, cells without seed coats were not damaged and the frequency histograms of comet length showed almost the same pattern as that for control. At acceleration voltages higher than 200kV, the cells were distributed into two categories; DNA comets with a short tail (with little DNA damages, less than 70μm in the comet length, ) and DNA comets with long tails (with sever strand breaks, more than 130μm in the comet length). The ratios of damaged cells increased with increasing acceleration voltage. The growths of rice seedlings were not affected by the treatment with electrons at up to 200kV. On the contrary, the cells of gamma-irradiated seed showed small variations in the comet length, and which were depending on radiation dose. The individual cells of gamma-irradiated seeds at 1kGy showed shorter comet than the damaged cells with soft electron, seed treated with gamma rays (1-5kGy) did not shoot nor root.
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  • Distribution of Microorganisms in Herb Medicines and Their Decontamination by Gamma-irradiation
    Hitoshi Ito, Hiroyuki Kamakura, Setuko Sekita
    1999 Volume 34 Issue 1-2 Pages 16-22
    Published: September 30, 1999
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5986/jrafi.34.16
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    Herb medicines are traditional medicine in Japan and have been used for medical treatment. These herb medicines are contaminating frequently by microorganisms which has possibility to cause opportunistic diseases. Recently, hygienic standard of herb medicines become more strict than before, and it needs to decontaminate microorganisms by some treatments. However, chemical treatments such as by ethylene oxide fumigation leave toxic residues in the herbs while steam sterilization decrease medicinal components. From study on the distribution of microorganisms in 31 samples of selected herb medicines, colony forming units of total aerobic bacteria were determined to be 1.9 × 102 to 1.4 × 108per gram in 30 samples. Coliforms were also determined to be 6.9 × 102 to 4.3 × 106 per gram in 16 samples. The main aerobic bacteria were identified as Bacillus pumilus, B.circulans, B. megaterium, Erwinia, EnterobacterandAcinetobacter, whereas consisted mainly of Enterobacter in coliform counts. Molds were determined to be 6.3 × 101 to 1.9 × 105 per gram which consisted mainly Aspergillus glaucus group, A. restrictus group, A. flavus group, A. ostianus, A. phoenicis, Penicillium, Tricoderma, Rhizopus and Alternaria in 25 samples. A study on the inactivation of microorganisms at sample No. S18 showed that a gamma-irradiation dose of 20 kGy was required to reduce the total aerobic bacteria and the coliforms below a detectable level, while radiation-resistant bacteria were survived at high doses more than 10 kGy consisted withAcinetobacter and Enterobacter. Molds were inactivated below 8 kGy except Alternaria. However, a dose of 10 kGy should be effective for the sample No. S18 to reduce the spore-forming bacteria, the fecal coliforms and the molds below a detectable level per gram. On the study of inactivation of microorganisms in many samples except the No. 18, all kinds of microorganism were inactivated below a detectable level at 10 kGy irradiation.
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  • Irradiation Effects for the Growth Inhibition of Weed Seeds Invaded from Foreign Countries
    Yasuyuki Takatani, Hitoshi Ito
    1999 Volume 34 Issue 1-2 Pages 23-29
    Published: September 30, 1999
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5986/jrafi.34.23
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    Weeds of foreign origin have been invaded through imported maize or dried grass which using for animal feeds, and causing serious damages to agricultural crops and farm animals in Japan. These weeds are spreading mainly through animal feeds to feces. For the purpose to decrease the damage from these weeds, we investigated the gamma-irradiation effect on 7 species of the weed seed to suppress the germination or elongation of stem and root. After the irradiation of the weed seeds, all species kept the ability of germination even at 4 kGy in petri dish cultivation, whereas decreased the germination ratio in some species. However, many species of weed decreased the ability on elongation of stem or root below 1 kGy irradiation. Furthermore, all of species lost the ability on the development of root hair and appearance of first leaf after germination of seeds below 1 kGy irradiation. From this study, necessary dose for growth inhibition was estimated to be 1 kGy which should be able to apply with combination treatment of the animal feeds for elimination of pathogenic bacteria such as salmonellae at 3 to 5 kGy irradiation.
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  • Sterilization of proteinaceous food additives by irradiation: Temperature dependent changes in intensity of ESR signals generated by electron beam irradiation
    Kazushi Sakaue, Yutaka Higashimura, Toru Hayashi, Setsuko Todoriki, Yo ...
    1999 Volume 34 Issue 1-2 Pages 30-36
    Published: September 30, 1999
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5986/jrafi.34.30
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    Thaumatin, egg white and soybean protein were selected as samples of proteinous food additives, and changes in the intensity of signals appearing in them after they had been irradiated with electron beams were measured by ESR. It was found by such measurement that the positions of signals of thaumatin and soy proteins are nearly the same. Changes in the intensity of radicals in thaumatin calculated on the basis of the coefficients of the respective approximations obtained by using thaumatin which had been irradiated and then stored at 4°C, 25°C, 37°C and 60°C showed that there is a temperature range to determine the remaining of such radicals (inner: 19.7°C, outer: 15.23°C) and that such radicals tend to decrease straight line-wise. It was confirmed that the intensity of signals in the protein powder such thaumatin and soy protein would not be affected at the storage condition below 15°C.
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  • Consumer attitude surveys toward irradiated foods in Japan
    Masakazu Furuta
    1999 Volume 34 Issue 1-2 Pages 51-62
    Published: September 30, 1999
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5986/jrafi.34.51
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  • Current status of food irradiation in the world
    Setsuko Todoriki
    1999 Volume 34 Issue 1-2 Pages 63-65
    Published: September 30, 1999
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.5986/jrafi.34.63
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