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Volume 50 (2009)
- Issue 6 Pages 279-
- Issue 5 Pages 191-
- Issue 4 Pages 153-
- Issue 3 Pages 109-
- Issue 2 Pages 47-
- Issue 1 Pages 1-
Volume 50, Issue 4
Displaying 1-6 of 6 articles from this issue
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Originals
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Yusuke SHIBAHARA, Itta YAMADA, Yoshihiko UESAKA, Noriko UNEO, Akihisa ...2009 Volume 50 Issue 4 Pages 153-159
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSWhen unheated whole samples of crustaceans (shrimp, prawn and crab) were analyzed with our ELISA kit (FA test EIA-Crustacean ‘Nissui’) using anti-tropomyosin antibodies, a remarkable reduction in reactivity was recognized. This reduction in activity was found to be due to the digestion of tropomyosin during the extraction process by proteases contained in cephalothorax. To avoid the digestion of tropomyosin by proteases, we developed an extraction method (heating method) suitable for the detection of tropomyosin in unheated crustaceans including cephalothorax. Experiments with unheated whole samples of various species of crustaceans confirmed that the heating method greatly improved the low reactivity in the standard method; the heating method gave extraction efficiencies of as high as 93-107%. Various processed crustaceans with cephalothorax, such as dry products (unheated or weakly heated products) and pickles in soy sauce (unheated products), that showed low reactivity with the standard method were confirmed to give superior results with the heating method. These results indicated that the developed heating method is suitable for detecting unheated crustaceans with cephalothorax by means of the ELISA kit.View full abstractDownload PDF (806K) -
Motoh MUTSUGA, Youn-Kyu LEE, Yoko KAWAMURA, Kenichi TANAMOTO2009 Volume 50 Issue 4 Pages 160-168
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSA highly sensitive analytical method for 25 kinds of primary aromatic amines and azo-dyes in paper products was developed. Free amines and total amines of the samples were analyzed. The amount of each azo-dye was calculated from the amount of total amines by subtracting the amount of free amines. Amines and azo-dyes were migrated into water at 23°C for 24 hours. Free amines were extracted into dichloromethane after alkalization with sodium hydroxide solution. Azo-dyes were reduced to amines with sodium dithionite, alkalized, and then extracted into dichloromethane as total amines. They were determined by GC/MS. The recoveries of 100 μg/kg amines spiked into migration solution were in the range of 69-122%, except for 4,4'-oxydianiline and 4,4'-diaminodiphenylmethane which gave recovery rates of approximately 40%. The determination limits of amines were 4-20 μg/kg in paper. Amines and azo-dyes were surveyed in 17 kinds of base paper and 16 kinds of paper products for food contact use. Aniline was detected at levels of 4-20 μg/kg from most recycled papers, whereas the other amines were not detected in any sample.View full abstractDownload PDF (596K) -
Yoshimasa KASAHARA, Takeshi ITOU2009 Volume 50 Issue 4 Pages 167-172
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSA simple method was developed for determination of illudin S in fungi (Omphalotus guepiniformis: poisonous mushroom) and a food that caused food poisoning, using liquid chromatography tandem mass spectrometry (LC/MS/MS). Illudin S in fungi and the food that caused food poisoning was extracted with methanol and then cleaned up with an Oasis HLB cartridge. LC separation was performed with an octadecylated silica column (Inertsil ODS-3, 2.1 mm i.d.×150 mm) and a mobile phase of 0.1% formic acid-methanol (7 : 3) at a flow rate 0.2 mL/min. Mass spectral acquisition was performed in the positive mode and illudin S was targeted using multiple reaction monitoring (MRM) with electrospray ionization (ESI).
The recoveries of illudin S were 84-94% from edible fungi (Lentinula edodes, Pleurotus ostreatus and Panellus serotinus). The detection limits of illudin S in the fungi (L. edodes, P. ostreatus and P. serotinus) were 0.08-0.10 μg/g respectively. Illudin S was detected in the food that caused food poisoning at the level of 2.0 and 15.1 μg/g in the soup and fungi, respectively. The recovery of illudin S from a mushroom soup (cooked at 100°C for 10 min) sample which simulated food poisoning was 74.8%. These results indicate that the developed method is suitable for the determination of illudin S in fungi (O. guepiniformis) and foods that caused food poisoning.View full abstractDownload PDF (574K)
Notes
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Hiroyoshi HARA, Yuji OHASHI, Toshio SAKURAI, Kazuhiro YAGI, Tomohiko F ...2009 Volume 50 Issue 4 Pages 173-177
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSThe influence of Nisaplin, which contains 2.5% nisin, on the growth of Listeria monocytogenes in Karashi-mentaiko (red-pepper seasoned cod roe) was investigated. The MICs of Nisaplin for L. monocytogenes (108 CFU/mL) were measured; seven isolates showed a value of 1,600 μg/mL and one isolate showed a value of 800 μg/mL. All L. monocytogenes isolates had a MIC of 800 μg/mL at 106 CFU/mL. The number of L. monocytogenes in Karashi-mentaiko stored at 4°C was decreased by Nisaplin added at 60 and 600 μg/g. These results indicated that Nisaplin effectively inhibits the growth of L. monocytogenes in Karashi-mentaiko.View full abstractDownload PDF (138K) -
Hiroyuki HASHIMOTO, Kanako ITO, Hiroyuki TANAKA, Hiroshi AKIYAMA, Reik ...2009 Volume 50 Issue 4 Pages 178-183
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSA polymerase chain reaction (PCR) method for verifying the allergen labeling of foods (i.e., the presence of wheat, buckwheat, or peanut) was adopted as the official Japanese identification test by the Ministry of Health, Labour and Welfare of Japan in 2002. We have verified the wheat labeling of several commercial food items by using the adopted PCR method. The study has revealed that some foods with positive results in the screening test yielded negative results in the identification test. When the result of the screening test disagrees with that of the identification test, the validation of food labeling is remarkably difficult. Therefore, we developed a nested PCR method with high sensitivity and specificity and employed this method in our routine testing as necessary. In this study, we examined 11 types of models of processed foods containing 10 μg/g wheat protein by using the adopted PCR and nested PCR methods; these samples were prepared by various processes and had varying physical properties. The adopted and nested PCR methods enabled the detection of wheat in 8 and 10 types of food models, respectively. The reasons for the failure in detecting the food allergens include DNA fragmentation due to the processing of food and the presence of DNA from other sources in the extracted DNA. In both PCR methods, an increase in the amount of template DNA in the PCR mixture enabled the detection of wheat DNA in all the food samples, but an excessive increase in the amount of template DNA hindered PCR amplification. These results indicate that an increase in the amount of template DNA increases the efficiency of the detection of allergens in processed foods by conventional PCR. Further investigation is needed to remove factors that inhibit PCR amplification of the extracted DNA.View full abstractDownload PDF (534K)
Report
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Satoshi TAKATSUKI, Takahiro WATANABE, Takatoshi SAKAI, Rieko MATSUDA, ...2009 Volume 50 Issue 4 Pages 184-189
Published: August 25, 2009
Released on J-STAGE: September 10, 2009
JOURNAL FREE ACCESSPerchlorate (ClO4-) is both a naturally occurring and artificial compound, and it inhibits iodide uptake into the thyroid gland and disturbs thyroid function. It has been detected in many foods in the United States.
In order to investigate perchlorate contamination in foods in Japan, perchlorate level in 82 leafy vegetable samples and 20 bottled mineral water samples was measured using a procedure based on the FDA's procedure, employing IC-MS/MS with 18O4-labeled perchlorate as an internal standard.
Among 82 leafy vegetable samples tested, perchlorate levels were under the LOQ (0.3 ng/g) in 3 samples and ranged from 0.3 ng/g to 29.7 ng/g in 79 samples. In 20 bottled water samples, perchlorate was under the LOQ (0.1 ng/mL) in 14 samples and ranged from 0.14 ng/mL to 0.35 ng/mL in 6 samples.View full abstractDownload PDF (536K)
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