2005 Fiscal Year Final Research Report Summary
Culture-dependent and -independent analyses of microbial flora of funazushi and search for Lactococcus garvieae, an equol-producing bacterium
| Project/Area Number |
16380143
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fisheries chemistry
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| Research Institution | Tokyo University of Marine Science and Technology |
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Principal Investigator |
FUJII Tateo Tokyo University of Marine Science and Technology, Department of Food Science and Technology, Professor, 海洋科学部, 教授 (30093305)
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| Project Period (FY) |
2004 – 2005
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| Keywords | funazushi / fermented fish / lactic acid bacteria / PCR-DGGE / Lactobacillus / microbial flora / equol |
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| Research Abstract |
Microbial flora during the fermentation of funazushi, crucian carp fermented with rice, were studied both by culture-dependent method with SSCP (single strand conformation polymorphism) analysis and by culture-independent DGGE (denaturing gradient gel electrophoresis) method.
Microbial count increased from 10^2cfu/g at the beginning of the fermentation to 10^8cfu/g after 3 days and pH dropped from 6.5 to below 4.0 within 7 days of fermentation. Dominant microflora of funazushi by culture method were Staphylococcus spp. at the early stage, Lactobacillus plantarum from 14^<th> to 90^<th> day, and thereafter L.parakefiri. Yeasts of Candida parapsilosis, C.versatilis, etc were also detected. As for the formation of fermentable sugars from rice-starch necessary for the growth of lactic acid bacteria, Bacillus strains, showing high amylolytic activity, appeared in the early stage were thought to be responsible. By the DGGE analysis, Staphylococcus spp. and some variety of other bacteria were detected at the early stage of fermentation, while L.plantarum, L.curvatus, L.acetotolerans, etc were detected after the day 7. This is the first description to show the existence of L.acetotolerans in fermented seafoods.
Further, Lactococcus garvieae known as producer of equol, postulated inhibitory factor in prostate cancer, was searched for in 60 funazushi samples. However, L.garvieae was not detected both by culture and PCR methods
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