FOOD IRRADIATION, JAPAN

Sensitivity of Microorganisms be distributed through Japanese Tea manufacturing process by Radiation

Mayumi Ogura, Syojiro Kimura, Yasushi Sugimoto, Naonobu Jo, Kazuyo Nos ...

2002 Volume 37 Issue 1-2 Pages 1-5
Published: September 30, 2002
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.37.1

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The number of bacteria adhering to Japanese tea is 10⁷-10⁸ cfu/g in picked fresh tea leaves (almost radiation irresistance), decreasing every heat-treatment in manufacturing process to 10³-10⁴ cfu/g in tea on the market (only radiation resistance). Stillmore, its decreasing one figures after half a year by effect of anti-bacterium component contained Japanese tea. The number of fungi adhering to almost samples is below 50cfu/g, but that adhering to some powdered tea is 10² cfu/g. At heat treatment (80°C, 15min), the number of bacteria decrease very little. The other side, by EB-irradiated treatment (2kGy), its below 10² cfu/g (D₁₀-value;1.4-3.8kGy). The needed dose to decrease 10² cfu/g is 0.9-2.5kGy.

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Comparison of DNA comet assay and germination test (Half-Embryo-test) in gamma-irradiated Cherry Seeds

Setsuko Todoriki, Toru Hayashi

2002 Volume 37 Issue 1-2 Pages 6-11
Published: September 30, 2002
Released on J-STAGE: February 25, 2011

DOIhttps://doi.org/10.5986/jrafi.37.6

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Cherry fruits were irradiated with gamma-rays at doses up to 200Gy (effective dose for disinfestation of codling moth), and DNA strand break in seed embryos was investigated by using alkaline comet assay. Immediately after irradiation (≥100Gy), DNA from embryos produced comets with a long and wide tail due to fragmentation. In control cells, DNA relaxed and produced comet with very short tail (with few strand break). After 72h storage, DNA from fruits irradiated at 200 Gy showed comets with little tail and tail moment of comets was same as un-irradiated control. These results indicate that the strand breaks of DNA caused by irradiation in fresh seed embryo are repaired during storage. On the contrary, the ability of germination lost by irradiation did not restored, a dose of 100Gy and more retarded shoot elongation. In cherries irradiated at 100 Gy, the shooting percentage was less than 50% at 4th day after incubation. Germination test (Half embryo test) can be discriminate between irradiated and un-irradiated cherries.

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Detection of irradiated strawberries by identifying ESR peak of irradiated cellulose component

Michiko Goto, Hiroko Tanabe

2002 Volume 37 Issue 1-2 Pages 12-16
Published: September 30, 2002
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.37.12

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The method of detecting low-dose irradiated strawberries by identifying ESR peak of irradiated cellulose component was studied. Ratio of peak height (S) of high magnetic field cellulose component, and noise width (N) of either irradiated or unirradiated seeds of strawberries were compared. In this study, sample was identified to be irradiated when S/N ratio of ESR spectrum of 4 min. sweep time was above 0.7. In the case of S/N ratio below 0.7, when the S/N ratio of integrated ESR spectrum, obtained from measuring 10 times with 1 min. sweep time was above 1.0, the sample was identified to be irradiated. The result suggests that S/N ratio is a good marker to detect the irradiation. The strawberries irradiated above 0.5kGy was able to bedetected after 3 days storage at room temperature, after 21 days refrigeration and after 60 days freezing, respectively.

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Consideration on detection of irradiated rainbow trout by ESR method and 2-alkylcyclobutanone analysis

Hiroko Tanabe, Michiko Goto

2002 Volume 37 Issue 1-2 Pages 17-23
Published: September 30, 2002
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.37.17

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Relative ESR strength of rib, backbone and opercular bone from irradiated culture rainbow trout was direct proportional to dose between 0.56kGy and 5.7kGy. Relative ESR strength of rib was higher than that of backbone. Although only 5mg of otolith was obtained from one rainbow trout, bone density of otolith is so high that relative ESR strength of otolith showed about 20-fold higher value than that of rib.
In GCMS-SIM analysis of RCB, radiolyticompounds of lipid of fish meat, the amount of both DCB and TCB formed, estimated from ion concentrations of m/z98, were direct proportional to dose between 1.1kGy and 11.1kGy. Neither DCB nor TCB was detected in unirradiated sample. The ratio of amount of DCB formed to amount of TCB formed was nearly 4.4, which is the ratio of palmitic acid content to stearic acid content in rainbow trout, denoted in Standard Tables of Food Composition in Japan; Lipid composition of Foods.
Finally, we propose to use detection of radiolytic compound, RCB, and measurement of ESR of high-density bone together for reliable identification of irradiated fish.

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The present status of identification methods of irradiated foods

Makoto Miyahara

2002 Volume 37 Issue 1-2 Pages 29-47
Published: 2002
Released on J-STAGE: February 26, 2013

DOIhttps://doi.org/10.5986/jrafi.37.1-2_29

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The Status of Food Irradiation

A Report of 18th Annual Meeting of ICGFI

Hiromi Sunaga

2002 Volume 37 Issue 1-2 Pages 49-52
Published: September 30, 2002
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.37.49

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Irradiation of herbs and spices in Australia and New Zealand

About ANZFA Food Standard Code

Setsuko Todoriki

2002 Volume 37 Issue 1-2 Pages 53-59
Published: September 30, 2002
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5986/jrafi.37.53

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