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Volume 51, Issue 1
Displaying 1-8 of 8 articles from this issue
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Originals
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Koichi INOUE, Yukiko YOSHIMI, Tomoaki HINO, Hisao OKA2010 Volume 51 Issue 1 Pages 1-9
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSAn LC/ESI (positive-mode)-MS/MS method was developed for simultaneous quantification of 8 macrocyclic lactones (abamectin B1a, abamectin 8,9-Z isomer B1a, emamectin benzoate B1a, emamectin benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin) in animal tissues, egg, milk and honey. The separation was achieved on a TSK-GEL ODS 100 V column (2.0×50 mm, 3 μm) with a mobile phase consisting of 0.1% formic acid in acetonitrile, and 0.1 mM ammonium formate-0.1% formic acid in water, at a flow rate of 0.2 mL/min with gradient elution. Linear calibration plots were obtained with high correlation coefficients (r=0.998-0.999). The LOQ and LOD ranged from 0.02-1.5 ng/mL and 0.1-5 ng/mL, respectively. Average recoveries were in the range of 70.8-117.1% with associated RSD values<15% (n=10) for repeatability and reproducibility. The spiking levels for recoveries and RSDs met the validation criteria for Japanese maximum residue limits (MRLs). Based on these results, the proposed analytical method has been proven to be highly efficient and suitable for routine determinations of macrocyclic lactones in animal food matrices.View full abstractDownload PDF (809K) -
Mihoko MURATA, Sumi SUGIYAMA, Aiko UEDA, Masataka ISHINAGA2010 Volume 51 Issue 1 Pages 10-18
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSThe contents of nitrate and nitrite in menus containing more than 350 g of vegetables per day were investigated. The amounts of vegetables in menu A developed by female students and menu B taken from a recipe book were 350±2 g and 457±77 g, respectively. The average content of the nitrate was 321.0±139.3 mg (104.2-636.9 mg) in menu A, and 245.7±90.7 mg (140.1-507.3 mg) in menu B. Sixteen and thirteen samples exceeded the ADI in menus A and B, respectively. This may be because menu A contained more raw vegetables than menu B (menu A; 120±58 g, menu B; 72±71 g). The contents of nitrite in menu A and B were 1.2±0.3 mg (0.7-1.8 mg) and 2.8±0.9 mg (1.3-4.6 mg), respectively, and 6 samples in menu B exceeded the ADI. Intake of 350 g of vegetables or more in a day may reguire careful consideration of selection, frequency of use and cooking method, especially for vegetables with high nitrate content. A questionnaire to female students showed that 80% or more of students recognized that vegetables containing high contents of nitrate, such as spinach and komatsuna, should be boiled before eating them.View full abstractDownload PDF (936K) -
Naoki SUGIMOTO, Atsuko TADA, Takako SUEMATSU, Kazunori ARIFUKU, Takesh ...2010 Volume 51 Issue 1 Pages 19-27
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSA quantitative NMR (qNMR) method was applied for the determination of carminic acid. Carminic acid is the main component in cochineal dye that is widely used as a natural food colorant. Since several manufacturers only provide reagent-grade carminic acid, there is no reference material of established purity. To improve the reliability of analytical data, we are developing quantitative nuclear magnetic resonance (qNMR), based on the fact that the intensity of a given NMR resonance is directly proportional to the molar amount of that nucleus in the sample. The purities and contents of carminic acid were calculated from the ratio of the signal intensities of an aromatic proton on carminic acid to nine protons of three methyl groups on DSS-d6 used as the internal standard. The concentration of DSS-d6 itself was corrected using potassium hydrogen phthalate, which is a certified reference material (CRM). The purities of the reagents and the contents of carminic acid in cochineal dye products were determined with SI-traceability as 25.3-92.9% and 4.6-30.5% based on the crystalline formula, carminic acid potassium salt trihydrate, which has been confirmed by X-ray analysis. The qNMR method does not require a reference compound, and is rapid and simple, with an overall analysis time of only 10 min. Our approach thus represents an absolute quantitation method with SI-traceability that should be readily applicable to analysis and quality control of any natural product.View full abstractDownload PDF (809K)
Notes
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Rima TANABE, Byung-Yoon CHA, Takayuki YONEZAWA, Je-Tae WOO, Kazuo NAGA ...2010 Volume 51 Issue 1 Pages 28-31
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSEnterohaemorrhagic Escherichia coli O-157 : H7 produces verotoxins called Shiga toxin or Shiga-like toxin. The type 1 and type 2 toxins present different immunological and physicochemical characteristics, and cause symptoms such as watery diarrhea, bloody diarrhea, severe stomach ache, fever and vomiting. The toxins can be assayed by several methods, including ELISA and PCR, with some limitations as to sensitivity. In the present study, we used a ProteoChip, which requires smaller volumes of reagents and allows detection of lower concentrations of the toxins, compared with the conventional assay.View full abstractDownload PDF (527K) -
Junichi MANO, Yuka YANAKA, Hiroshi AKIYAMA, Reiko TESHIMA, Satoshi FUR ...2010 Volume 51 Issue 1 Pages 32-36
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSThe Bt11 maize-specific qualitative detection method based on polymerase chain reaction (PCR) in the JAS analytical test handbook has been widely used for administrative monitoring of GM crops and quality control of commercially distributed grains. In the present investigation, some apparently false-positive detections were observed in assays using the Bt11 maize-specific method, and these erroneous results were proved to have been caused by non-specific DNA amplification. We improved the detection method to reduce non-specific amplification by decreasing the concentration of magnesium ions in the PCR mixture. The subsequent evaluation of analytical performance demonstrated no marked difference between the currently used and the improved methods, except for the reduced non-specific amplification. We conclude that the currently used standard method should be replaced with the improved method for the reliable detection of Bt11 maize.View full abstractDownload PDF (239K)
Reports
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Kunihiko TAKAHASHI, Rie ISHII, Ryuji MATSUMOTO, Masakazu HORIE2010 Volume 51 Issue 1 Pages 37-42
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSIn the inspection of genetically modified rice, rice taxon-specific DNA could not be detected in processed rice food (bifun: rice vermicelli). The effects of using PCR the ratio of rice powder content and temperature of processing on the detection of taxon-specific DNA were examined by means of processing model experiments using cornstarch with 0, 2, 5, 10% rice powder by weight. Cornstarch and rice powder were blended with water and subjected to heating, steam-treatment, and autoclaving. The rice taxon-specific DNA was detectable in 2% rice powder following heat and steam treatments. After autoclaving, rice taxon-specific DNA was detected only in the 10% rice powder product. In the processing model experiment using rice powder, it was found that autoclaving caused severe DNA degradation.View full abstractDownload PDF (571K) -
Eri SHIMIZU, Satoshi FUTO, Tomoko MASUBUCHI, Yasutaka MINEGISHI, Masak ...2010 Volume 51 Issue 1 Pages 43-47
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSPolypropylene microtubes (tubes) are generally used for bio-material tests in addition to PCR tests such as genetically modified organism (GMO) testings. However, the choice of suitable tubes is quite important, because it might influence the results: DNA binding and/or elution of chemical substances sometimes occurs. In this study, we established methods to select tubes with the most suitable characteristics for DNA testing.View full abstractDownload PDF (484K) -
Yuji NAGASHIMA, Isao MATAKI, Maho TOYODA, Hiroshi NAKAJIMA, Kingo TSUM ...2010 Volume 51 Issue 1 Pages 48-51
Published: February 25, 2010
Released on J-STAGE: March 06, 2010
JOURNAL FREE ACCESSChanges in tetrodotoxin (TTX) content of the puffer fish Takifugu rubripes during seed production were examined. Two mature female puffer fish T. rubripes (samples 1 and 2) that contained TTX were used. The toxic eggs were artificially fertilized, and hatchlings were reared in an indoor tank for 50 days and then in a netcage at sea for an additional 48 or 38 days. The TTX content of the fertilized eggs of sample 1 was initially 13.0 μg TTX/g, transiently increased to 67.6 μg TTX/g at 4 days after hatching, and then gradually decreased to 0.28 μg TTX/g at 98 days. In contrast, the total TTX content in an individual was 0.016 μg TTX at the fertilization stage and 0.01-0.03 μg TTX at the larval stage until 30 days after hatching. Thereafter, the total TTX content increased remarkably during culture in the netcage at sea, reaching 4.80 μg TTX at 98 days. Change in the TTX content of sample 2 showed a similar tendency to that of sample 1. The present study showed that the TTX content per gram of puffer fish body weight decreased during progression from fertilized eggs to juveniles, whereas the total TTX content increased.View full abstractDownload PDF (122K)
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