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Volume 48, Issue 1
Displaying 1-4 of 4 articles from this issue
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Takashi CHIBA, Tomoaki WAUKE, Kenji SADAMASU, Kazuyoshi YANO, Satoshi ...2007 Volume 48 Issue 1 Pages 1-7
Published: February 25, 2007
Released on J-STAGE: April 28, 2008
JOURNAL FREE ACCESSThe identification of 20 strains of yeasts isolated from foods by means of DNA sequence analysis with two kinds of universal primers for the rDNA region was examined, and the results were compared with those of the conventional phenotyping test using API 20C AUX. In the analysis of the 26S region, all 20 yeast strains tested were identified at the species level. In the ITS1 region, 16 strains were also classified at the species level. In addition, all results of DNA sequence analysis were consistent with those of the phenotyping test at the genus level. Furthermore, DNA sequence analysis was able to identify causative yeasts observed in two suspect foods, though phenotyping tests alone failed to identify them.View full abstractDownload PDF (736K) -
Tomoaki TSUTSUMI, Yoshiaki AMAKURA, Kumiko SASAKI, Tamio MAITANI2007 Volume 48 Issue 1 Pages 8-12
Published: February 25, 2007
Released on J-STAGE: April 28, 2008
JOURNAL FREE ACCESSWe examined the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in muscle and gut tissues from Japanese common squid and saury. These body parts are often eaten in Japan, so it is important to measure their dioxin concentrations and evaluate the risks to consumers. The toxic equivalent (TEQ) concentrations in the squid gut samples (1.0 to 14 pg-TEQ/g fresh weight, n=3) were 50-fold larger than those in the muscle tissues (0.020 to 0.22 pg-TEQ/g fresh weight, n=3) taken from the same samples. By contrast, the TEQ concentrations in the saury gut samples (0.35 to 0.63 pg-TEQ/g fresh weight, n=3) were only 1.1- to 1.7-fold greater than those in the muscle tissues (0.33 to 0.37 pg-TEQ/g fresh weight, n=3) from the same samples. The TEQ contents in the squid gut tissues ranged from 60 to 990 pg-TEQ/squid, accounting for about 95% of the total dioxin content of the edible parts of the samples. By contrast, the TEQ contents in the saury gut tissues ranged from 4.4 to 12 pg-TEQ/saury, accounting for less than 25% of the total dioxin content of the edible parts of the samples. These tissues showed comparable PCDD/PCDF-congener and dioxin-like PCB-isomer profiles in both species. The results indicate that squid gut tissues occasionally contain high levels of dioxins, and consumption of this foodstuff could potentially significantly increase the dietary intake of dioxins.View full abstractDownload PDF (747K) -
Mohamad SAMSUR, Tomohiro TAKATANI, Yasunaga YAMAGUCHI, Takefumi SAGARA ...2007 Volume 48 Issue 1 Pages 13-18
Published: February 25, 2007
Released on J-STAGE: April 28, 2008
JOURNAL FREE ACCESSThe paralytic shellfish poison (PSP)-producing dinoflagellate Gymnodinium catenatum (Gc) was fed to the short-necked clam Tapes japonica, and the accumulation, transformation and elimination profiles of PSP were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested most of the Gc cells (4×106 cells) supplied as a bolus at the beginning of the experiment, and accumulated a maximal amount of toxin (181 nmol/10 clams) after 12 hr. The rate of toxin accumulation at that time was 16%, which rapidly decreased thereafter. During the rearing period, a variation in toxin composition, derived presumably from the transformation of toxin analogues in the clams, was observed, including a reversal of the ratio of C2 to C1, and the appearance of carbamate (gonyautoxin (GTX) 2, 3) and decarbamoyl (dc) derivatives (decarbamoylsaxitoxin (dcSTX) and dcGTX2, 3), which were undetectable in Gc cells. The total amount of toxin contained in clams and residue (remaining Gc cells and/or excrement in the rearing tank) gradually declined, and only about 1% of the supplied toxin was detected at the end of the experiment.View full abstractDownload PDF (450K) -
Yoshiaki KASAI, Bon KIMURA, Yosuke TAJIMA, Tateo FUJII2007 Volume 48 Issue 1 Pages 19-26
Published: February 25, 2007
Released on J-STAGE: April 28, 2008
JOURNAL FREE ACCESSA duplex quantitative polymerase chain reaction (PCR) assay for Clostridium botulinum types A and B was developed. The sensitivity and specificity of the assay were verified by using 6 strains of type A, 7 strains of type B, and 14 genera of 42 non-C. botulinum types A and B strains, including C. botulinum types C, D, E, F, and G. In pure culture, the detection limit was 102 CFU/mL for type A and 103 CFU/mL for type B. In mushroom broth, increases in the amounts of C. botulinum types A and B could be monitored separately (the quantifiable range was 102 to 106 for type A and 102 to 107 for type B) from each sample that contained a large number of background bacteria, and toxin could be detected much earlier than with mouse assay. These results suggest that duplex quantitative PCR methods are useful to detect and quantify C. botulinum types A and/or B toxin genes.View full abstractDownload PDF (427K)
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