Japanese Journal of Food Microbiology
Online ISSN : 1882-5982
Print ISSN : 1340-8267
ISSN-L : 1340-8267
Volume 36 , Issue 1
Showing 1-13 articles out of 13 articles from the selected issue
Special Lecturer
Education Lecturer
Symposium I: For Rapid Detection and Response and Prevention of Sporadic Food Poisonings Dispersed in Broad Area
Special Symposium: Food Microbiology for Health Promotion
  • Ayasa Kamezaki, Sakuo Yamada
    2019 Volume 36 Issue 1 Pages 40-46
    Published: March 31, 2019
    Released: April 03, 2019

    The microbicidal effect of yellow Chinese chive against Candida albicans was assessed using mycological and morphological examinations. When C. albicans was treated with yellow Chinese chive for more than 24 hr, the number of viable cells was significantly decreased and scanning electron microscopy (SEM) revealed that the surfaces of the microbes were partially damaged. Notably, yellow Chinese chive appeared to be more effective than standard Chinese chive against C. albicans. The results of microplate biofilm assays demonstrated that C. albicans biofilm formation was suppressed by pre-treatment with yellow Chinese chive. The suppression of biofilm formation by yellow Chinese chive treatment was also confirmed with the SEM observations, which demonstrated that the amounts of matrix and slime-like substances around the surface of the pre-treated cells were both lower than those in control cells. These results suggest that yellow Chinese chive not only induced damage to the cell surface of C. albicans but also suppressed biofilm formation by these cells.

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Short Paper
  • Yusuke Chiba, Kyohei Sakata, Yuka Furui, Aya Tamura, Kunihiko Takahash ...
    2019 Volume 36 Issue 1 Pages 47-52
    Published: March 31, 2019
    Released: April 03, 2019

    We developed a multiplex loop-mediated isothermal amplification (mLAMP) assay to discriminate between Campylobacter jejuni and C. coli. The mLAMP assay is based on the fluorescence intensity of a fluorescent intercalator, which indicates whether DNA amplification has occurred. After the mLAMP reaction, two specific DNA products are discriminated based on differences in melting temperatures (Tm values). The mean Tm value obtained for C. jejuni by this assay was 84.26±0.19 and 88.34±0.30℃ for C. coli. The assay correctly discriminated between 34 C. jejuni strains and seven C. coli strains, and other bacteria associated with food poisoning were not detected. In sensitivity tests, the mLAMP assay effectively detected C. jejuni at levels of 7.3 cfu/test and C. coli at 13 cfu/test. In an assessment of viable bacterial counts and detection times, correlations in the range 10–104 cfu/test were obtained for both C. jejuni and C. coli (R2>0.9). In an analysis of five chicken samples using the mLAMP assay, C. jejuni was detected in three samples and C. coli was detected in one sample. These results corroborated those obtained based on bacterial cultures, but were obtained more rapidly. In conclusion, the developed mLAMP assay is a highly specific, sensitive and rapid tool for discriminating between C. jejuni and C. coli.

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