Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi)
Online ISSN : 1882-1006
Print ISSN : 0015-6426
ISSN-L : 0015-6426
Volume 25 , Issue 4
Showing 1-15 articles out of 15 articles from the selected issue
  • Keiko SATO, Hirokazu OGIHARA, Misao HARUTA
    1984 Volume 25 Issue 4 Pages 289-296_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Comparative studies on the aminopeptidase test and the selective media combination method for the analysis of bacterial flora in foods were performed. The results were as follows.
    1) The aminopeptidase test was found to be a reliable method to differentiate bacteria into gram-positive and gram-negative categories.
    2) The aminopeptidase test was more reliable and simpler than the selective media combination method using phenethyl alcohol agar for gram-positive bacteria and CVT agar for gram-negative bacteria.
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  • A New Type of Flat Sour Spoilage-VII
    Akihiko NAKAYAMA, Hajime KADOTA, Junko SONOBE
    1984 Volume 25 Issue 4 Pages 297-309_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Fifty-two strains isolated from spoiled canned coffee and “Shiruko” (a sweet bean drink) were examined taxonomically. All the isolates had the same morphological, cultural, and biochemical characteristics except for reduction of nitrate. Therefore, they were divided into two groups (Group A and Group B). The isolates of Group A reduced nitrate to nitrite but those of Group B did not.
    Their principal characteristics, which are gram-positive, rod-shaped, obligate-anaerobic, spore-forming, and thermophilic, led us to identify the isolates as members of the genus Clostridium or the genus Desulfotomaculum. As of April 1983, the genus Clostridium has 5 thermophilic species out of 82 approved species and the genus Desulfotomaculum has one thermophilic species out of 4 approved species. Comparison of the isolates with the published descriptions (G+C content, sulfate reduction, nutritional requirement, etc.) of the 6 thermophilic species reveals that the isolates are most similar to Clostridium thermoaceticum.
    A comparison of representative isolates of Groups A and B with a reference strain (Clostridium thermoaceticum DSM 521) showed that the morphological, cultural, and biochemical characteristics of Group A are the same as those of Clostridium thermoaceticum DSM 521 except for pH requirement and the inability to use xylose, while those of Group B are the same as those of the reference strain except for pH requirement and the inability to use xylose or to reduce nitrate.
    Thus, though a few characteristics of the isolates (Group A and Group B) are different from those of Clostridium thermoaceticum DSM 521, none of the differences seem sufficiently significant to distinguish the isolates from Clostridium thermoaceticum. These facts suggest that the isolates are identical with Clostridium thermoaceticum.
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  • Yoshiki ONJI, Masakiyo UNO, Kaoru TANIGAWA
    1984 Volume 25 Issue 4 Pages 310-316_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    A droplet counter-current chromatography (DCC) method for the separation of contaminants from lipids in fish samples has been developed for food contamination monitoring by GC/MS. Concurrently, the lipid constitution of fish extract has been investigated by HPTLC-densitometry.
    The main component of crude fish extract was triglyceride (TG) and the other components were diglyceride (DG), cholesterol (Ch), free fatty acid (FFA), monoglyceride (MG), phospholipids (PL), and unknowns.
    Various industrial chemicals and pesticides were eluted with good separation and reproducibility from DCC according to their partition coefficients between the stationary phase and mobile phase.
    After removal of almost all TG by acetonitrile n-hexane partition, the remaining lipid was subjected to DCC. Fish extract was fractionated into 8 fractions. These fractions could be concentrated to 0.1-1mL (from 1kg of fish).
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  • Kuni KATO, Tadayoshi NAKAOKA, Kazutoshi ITO
    1984 Volume 25 Issue 4 Pages 317-321_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Two kinds of plasticizers were identified in polyvinyl chloride (PVC) films used for food packaging. One of them was diisononyl adipate, and the other was a mixture of di-n-hexyl adipate, n-hexyl-n-octyl adipate, n-hexyl-n-decyl adipate, di-n-octyl adipate, n-octyl-n-decyl adipate, di-n-decyl adipate and acetyl tributyl citrate.
    A method for determination of these adipates was developed as follows: adipates extracted from PVC with n-hexane were converted to dimethyl adipate (DMA) by treatment with boron trifluoride methanol complex. After methyl esterification, 10% sodium sulfate solution was added to the reacted solution and the DMA and constituent alcohols formed were extracted with n-hexane and determined by gas chromatography. DMA and constituent alcohols could be analyzed simultaneously on a single column of 15% PEG-1000.
    The value of adipates was calculated from that of DMA and alcohols.
    The yields of DMA from various adipates were above 90%. The amounts of adipates in PVC films were 12.0-22.0%.
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  • Tadashi TERAMOTO, Riichi SAKAZAKI
    1984 Volume 25 Issue 4 Pages 322-328_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Taxonomic studies were carried out on 2, 842 strains of gram-negative, facultatively anaerobic, fermentative rods isolated from foods and environmental materials by means of a probabilistic method using a computer. Although coliforms included only a few species in the classification proposed by the Coli-Aerogenes Subcommittee in 1956, the 2, 842 strains studied were divided into 51 species.
    Strains showing an IMViC pattern on Escherichia coli included authentic E. coli and eight other species that probably originated from the environment. The majority of strains of E. coli were easily differentiated from other coliform organisms by their ability to grow at 44.5°, but 17% of lactose-fermenting and 16% of lactose-nonfermenting strains of E. coli failed to grow at this temperature. In addition, 13.3% of 188 E. coli strains were non- or late lactose-fermenters and 10.4% of 163 lactose-fermenting E. coli produced no gas, so that these strains did not serve as indicator organisms of fecal contamination. Thus, enterobacteria found in foods may not always indicate direct fecal contamination, but may often originate from environmental sources.
    It is discussed whether enterobacterial species other than E. coli should also be included in the indicator organisms of microbial standards for processed foods. Although the species found in foods in this study would be harmless to healthy persons, they have often been observed as opportunistic pathogens in hospitalized patients with some underlying diseases. It seems desirable, therefore, that separate microbial standards from those for public health should be applied to foods served to hospitalized patients.
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  • Shin-ichiro KATSUDA, Noriji TABA, Kenji CHIMI
    1984 Volume 25 Issue 4 Pages 329-333_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    The purpose of this study was to investigate toxic actions of gonyautoxins (GTXs), the major component of paralytic shellfish poison in Japan, on cardiovascular function and to compare the actions with those of tetrodotoxin (TTX). Circulatory effects of these toxins were assessed by means of electrocardiogram (ECG) and arterial pressure (AP) measurements in anesthetized intact rabbits. The ECG was measured with A-B lead and AP was measured in the aortic arch with a catheter-transducer system. The intravenous administration of GTXs or TTX produced hypotension. The latency of the hypotension due to GTXs was shorter than that due to TTX. In the ECG, GTXs induced sinus tachycardia, atrioventricular and intraventricular conduction defects which were prone to initiate paroxysmal ventricular tachycardia, fibrillation and flutter at large doses, while TTX caused sinus bradycardia and atrioventricular block only. However, the cardiovascular actions of GTXs were more transient than those of TTX.
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  • Akihiro IBE, Motohiro NISHIJIMA, Kazuo YASUDA, Kazuo SAITO, Hisashi KA ...
    1984 Volume 25 Issue 4 Pages 334-341_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    A method is described for the determination of low levels of ochratoxins A and B in foods by high performance liquid chromatography (HPLC). Ochratoxins were extracted from samples with the methanol-1% sodium bicarbonate system. The extracts were transferred to ether after acidification with phosphoric acid, then the ether layer was washed with water, dried with anhydrous sodium sulfate and evaporated to dryness. The residue was dissolved in chloroform (saturated with 1% ammonia water) and applied to a silica gel column (15% water content). The column was washed with 40ml of chloroform. Ochratoxins were eluted with 50ml of benzene-glacial acetic acid (9:1). The eluate was washed with water, dried with anhydrous sodium sulfate and evaporated to dryness, then the residue was subjected to HPLC after being dissolved in acetonitrile. The recoveries of ochratoxins added to foods at levels of 20 and 100ppb were in the range from 87% to 101% and the detection limit was 2.5ppb in samples.
    For chemical confirmation of ochratoxins A and B in samples, the methyl esters were prepared by heating at 100°C for 20 min with methanol-sulfuric acid. The identification limit was 2ppb in samples.
    By using this method, 171 commercial samples were analyzed. Ochratoxin A was detected in rye flour at a trace level (<2.5ppb)-20ppb.
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  • Takeji CHIKAMOTO, Takeshi MAITANI
    1984 Volume 25 Issue 4 Pages 342-346_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    A rapid and accurate method is presented for the simultaneous determination of ethanol and propionic acid in bakery products by gas chromatography. Ethanol and propionic acid were separated by steam distillation from samples acidified with phosphoric acid and collected into alkaline solution. The distillate was acidified by adding formic acid solution, and the resulting solution was injected directly into the gas-chromatographic column packed with porous polymer beads, with flame ionization detection. Recovery of both compounds added to cake at levels ranging from 0.2 to 2.0g/kg was more than 97%, the coefficients of variation being less than 5% for ethanol and 2% for propionic acid. The limit of determination for each compound was 0.05g/kg in bread and cake. This method is applicable to the determination of acetic acid in food when derivatives of acetic acid are not present.
    Fifteen samples of bread and cake were analyzed by the present method. Ethanol was detected in all the samples at the level of 0.07-19.3g/kg, and propionic acid was detected in 4 samples at the level of 0.04-0.69g/kg.
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  • Makoto YOSHIMOTO, Kuniaki NODA, Shoji HATANO, Tadao WATANABE
    1984 Volume 25 Issue 4 Pages 347-351_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    The effects of Amaranth, Ponceau 3R, Sunset Yellow FCF, and Rose Bengal on viability and RNA and protein syntheses were studied in suspensions of viable rat hepatocytes. Liver parenchymal cells were enzymatically prepared from normal adult rats by perfusion of the liver with buffer solution of 0.05% collagenase, followed by shaking of liver slices in the same solution. The cell yield was 60.5±15.8×106cells/g liver and the cell viability index was 87.0±2.4%. When the isolated hepatocytes were incubated in the presence of coal tar dyes at a concentration of 1mM for 4hr, a decrease in the cell viability was observed. In particular, the Rose Bengal-treated fraction showed a rapid decrease of the cell viability in comparison with other dye-treated fractions. 3H-Uridine incorporation into RNA was stimulated in the presence of Amaranth or Ponceau 3R. On the other hand, none of the coal tar dyes tested in this study had any effect on 14C-isoleucine incorporation into protein. These results suggest that the system of isolated hepatocytes may be a good model for studying the mechanism of action of toxic chemicals.
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  • Makoto YOSHIMOTO, Kuniaki NODA, Shoji HATANO, Tadao WATANABE
    1984 Volume 25 Issue 4 Pages 352-355_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Two groups of five rats were treated daily by gavage for 30 days, one with water (control) and one with Rose Bengal (300mg/kg of body weight/day) in water. The effects of this treatment on organ weight, liver components and RNA synthesis were studied. The administration of the dye to young adult male rats had no influence on growth rate, but caused a significant decrease in relative liver weight. The treatment with the dye had no effect on 3H-UTP incorporation into RNA or on RNA content in liver nuclei. However, the protein content in liver nuclei was significantly lower than in those from control rats. Furthermore, decreased lipid and glycogen contents in liver were observed. These results suggest that repeated oral administration of Rose Bengal might affect some metabolic system other than RNA synthesis.
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  • Toshibumi TSUZUKI, Hiroyuki SUNAGAWA, Yoshiaki ANDO
    1984 Volume 25 Issue 4 Pages 356-359_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    The effect of the composition of thioglycollate medium as a subculture medium on the subsequent sporulation of Clostridium perfringens NCTC 8238 in Duncan and Strong medium was studied. Sporulation varied greatly with the kinds of media used (from different manufacturers). Fluid thioglycollate medium (BBL) was found to be the best, although there was much variation in different lots of the medium. Some lots were not nearly so sporogenic as others. Replacement of Trypticase (BBL) in the medium by similar products from differene manufacturers resulted in markedly reduced sporulation. Again, variation in different lots of Trypticase was demonstrated, indicating that differences in ability to produce spores among lots of fluid thioglycollate medium are attributable to differences among lots of Trypticase. The percentage sporulation, irrespective of the Trypticase used, was greatly increased by decreasing the concentration of glucose from 0.5 to 0.1% in the thioglycollate medium and prolonging the incubation period of time from 16 to 24hr.
    Enterotoxin production was investigated in relation to sporulation by some other strains of the same organism.
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  • Ritsuko MURAKAMI, Kazunori YAMAMOTO, Takahisa KAMIYA, Michihiko KOMURO ...
    1984 Volume 25 Issue 4 Pages 360-365_1
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
    Sorbic acid in foods was extracted by dialysis, then 0.1M nitric acid and 1% iron (III) nitrate soln. were added to the extract and the mixture was heated in a boiling water bath. Next, thiobarbituric acid (TBA) was added to the reaction mixture in the boiling water bath and heated for 10 minutes. The reaction mixture was cooled to room temperature and the absorbance at 532nm was measured.
    It was found that this method could be applied to foods containing ethanol without difficulty and was not disturbed so much by other food additives probably used with sorbic acid. Thus, sorbic acid in various commercial foods could be determined in a short time by this method.
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  • Hirokazu OGIHARA, Keiko SATO, Yoshikazu SIMIZU, Misao HARUTA
    1984 Volume 25 Issue 4 Pages 366-370
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
  • Kazuo YASUDA, Motohiro NISHIJIMA, Kazuo SAITO, Hisashi KAMIMURA, Akihi ...
    1984 Volume 25 Issue 4 Pages 371-377
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
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  • Seiichi UENO, Noritaka OYAMADA, Kaoru KUBOTA, Mutsuo ISHIZAKI
    1984 Volume 25 Issue 4 Pages 378-382
    Published: August 05, 1984
    Released: December 11, 2009
    JOURNALS FREE ACCESS
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