• Food Science and Preservation
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• v.13 no.2
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• pp.211-215
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• 2006

Photostimulated luminescence (PSI) and thermoluminescence (TL) were analyzed for dried vegetables irradiated at 0, 1, 4 and 7 kGy, such as dried oak mushroom, spinach, radish leaves, water cress, radish, and pumpkin, to detect irradiation treatment. PSL results that photon counts for non-irradiated samples were lower than 700 that corresponds to negative, while those of irradiated samples over 1 kGy showed positive photon counts$(\geq5000)$, indicating irradiation treatment Meantime, TL ratio by normalization was lower than 0.021 in threshold value for non-irradiated samples and more than 0.653 for irradiated samples, and therefore it was possible to detect whether the 6 kinds of dried vegetables were irradiated or not by analyzing PSL and TL.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.173-177
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• 2001

A study was carried out to establish a detection method for imported sesame and perilla seeds using pulsed photostimulated luminescence (PPSL) whether they have been irradiated or not. Samples were packed in polyethylene bags and irradiated at 1, 5, and 10 kGy with a dose rate of 10 kGy/h. The whole sample of sesame and perilla and the minerals separated from seeds were introduced in the sample chamber and measured PPSL photon counts for 60 and 120 s. The PPSL photon counts of samples increased with increasing irradiation dose and showed a higher correlation coefficients in separated minerals than in sesame and perilla seeds themselves. These results suggest that imported sesame and perilla seeds be possibly detected by both their whole sample and separated minerals by PPSL measurements.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.498-501
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• 1998

It was determined whether photostimulated luminescence (PSL) is applicable to the detection of post-irradiation of foods by measuring PSL photon counts for unirradiated and irradiated pepper powder, dried herbs, fresh shrimp, potato, soybean, dried fig, chestnut, dried squid, and dried cod. The samples were irradiated with $^{60}Co\;{\gamma}-ray$ source and PSL photon counts were measured for them. The photon counts of unirradiated samples were lower than 2,000 for potatoes and less than 1,000 for the others. The photon counts of the irradiated samples except dried figs (0.5 kGy), chestnuts (0.2 kGy), and dried squid (0.5 kGy) were higher than 1,000, and the photon counts increased with dose. Thus, PSL might be applied to the primary detection of irradiated foods.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.136-141
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• 2010

This study attempted to determine whether Photostimulated Luminescence (PSL) is applicable for the detection of post-irradiated foods by measuring the PSL photon counts of unirradiated and irradiated dried spices and herbs. A total of 19 dried spices and herbs was irradiated with a $^{60}Co$ $\gamma$-ray source at 1, 5 and 10 kGy followed by measurement of PSL photon. The photon counts of unirradiated samples below 700 correspond to negative. Fifteen samples irradiated over 1 kGy showed photon counts of more than 5,000, indicating irradiation treatment. Intermediate counts (photon count 700-5,000) were observed in irradiated white/black pepper, nutmeg and cinnamon bark at 10 kGy. These results suggest that it is possible to detect whether dried spices and herbs were irradiated by analyzing PSL, with the exception of white/black pepper, nutmeg and cinnamon bark. Irradiated white/black pepper, nutmeg and cinnamon bark containing low levels of minerals were not sensitive to PSL. Therefore, further investigation is sugguested to be performed by Thermoluminescence (TL) analysis or another validated or standardized method.

• Journal of Radiation Industry
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• v.2 no.1
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• pp.27-34
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• 2008

Photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence (TL) analyses were conducted to detect whether 258 kinds of extracted and powdered forms food additives were irradiated or not. In a view of the PSL results, 9 kinds of the extracted and powdered samples (3.2%) showed over 5,000 photon counts $(60sec)^{-1}$ and these samples were judged to be irradiation-positive. Thirty nine kinds of the samples (15.6%) yielded 700~5,000 photon counts $(60sec)^{-1}$ and these samples were grouped into irradiation-potential, while the samples showed below 700 photon counts $(60sec)^{-1}$ sec were judged to be irradiation-negative. TL glow curves for minerals separated from 5 samples were detected at $150^{\circ}C$ with high intensity. However, TL analysis did not apply to other irradiation-positive and irradiation-potential samples because the minerals for TL detection were not separated from the samples. ESR measurements for irradiation-positive and irradiation-potential samples, judged by PSL detection, showed no specific signals to irradiation. The results indicated that PSL could be applied to identify irradiation treatment of extracted and powdered food additives, while TL was optional and ESR was not suitable for detection extracted and powdered food additives.

• Journal of Ginseng Research
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• v.37 no.4
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• pp.483-490
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• 2013

Gamma-irradiation (0-7 kGy) of ginseng is permitted in Korea for the purpose of microbial decontamination; with strict labeling, traceability and monitoring requirements. An identification study was conducted to determine the photostimulated-luminescence (PSL) and thermoluminescence (TL) properties of gamma-irradiated fresh and white ginsengs cultivated in different areas. Dose- dependent PSL-based screening was possible for white ginseng samples; however, inappropriate results from non-irradiated fresh ginseng samples were obtained, showing intermediate (700 to 5,000) or positive ($T_2$ >5,000, irradiated) PSL counts due to the abundance of minerals on the surfaces of the samples. TL analysis of separated minerals from all non-irradiated samples gave TL glow curves of low intensity with a maximum peak after $300^{\circ}C$. However, well-defined irradiation-specific (high intensity with a maximum peak at about $200^{\circ}C$) glow curves were observed for all the irradiated samples, regardless of their type and origins. TL ratios (first glow curve /second glow curve) were also determined to confirm the irradiated (>0.1) and non-irradiated (<0.1) results. SEM-EDX (scanning electron microscope-energy dispersive X-ray) and XRD (X-ray diffraction) spectroscopic analyses showed that feldspar and quartz minerals were the main source for the typical radiation-specific luminescence properties.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.123-126
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• 2001

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.127-130
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• 2001

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.200.2-200
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• 2001

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.152-157
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• 2001

Accumulated photon counts in immediate measurement after irradiation of marjoram, basil and thyme were shown to be below 625$\pm$162, 577$\pm$178 and 1261$\pm$640 Pc, respectively. The accumulated photon counts increased linearly with increasing irradiation doses up to 5 kGy and slightly increased from 5 kGy to 10 kGy. This trend was similar after storage periods. According to storage conditions, the difference of the accumulated photon counts was net clearly observed. The accumulated photon counts of irradiated spice samples decreased with increasing storage periods. The rate of decrease was higher in 5 and 10 kGy irradiated samples than that in 1 kGy, and in room conditions than that in darkroom conditions. The photon counts of the irradiated spice samples measured for 120 s were higher than those measured for 60 s. The irradiated spice samples showed higher photon counts than those of unirradiated samples in both room and darkroom conditions during all the storage periods. These results indicate that detection of irradiation was still possible after 24 weeks, although the PPSL signal of all spice samples decreased with increasing storage times.