Comparison of PCR-DGGE and PCR-SSCP Analysis for Microflora of Kaburazushi and Daikonzushi, Traditional Fermented Foods Made from Fish and Vegetables

摘要

Kaburazushi and daikonzushi are traditional lactic acid fermented foods made in the Hokuriku area of Japan. In kaburazushi processing, salted turnip (Brassica rapa var. glabra) and salted yellowtail (Seriola quinqueradiata) are fermented with malted rice for several days to 2 weeks in winter (0-10°C). Daikonzushi is made from Japanese white radish (Raphanus sativus var. raphanistroides), dried and leached Pacific herring (Clupea pallasi) and malted rice processed the same as for kaburazushi. To clarify the microbial property for the processing and human health, researchers employed a molecular approach to analyze the bacterial flora of kaburazushi and daikonzushi and their ingredients, combining PCR amplification of the V3 region of the 16S rDNA gene and Denaturing Gradient Gel Electrophoresis (DGGE) analysis. Furthermore we identified the isolated strains using PCR-Single Strand Conformation Polymorphism (SSCP) analysis. In the PCR-DGGE analysis, Lactobacillus sakei was detected as the predominant bacteria in both products. On the other hand, the bacterial DGGE band was not detected in salted turnip and salted yellowtail. L. sakei and Leuconostoc mesenteroides were isolated and identified as the predominant lactic acid bacteria in the products by PCR-SSCP analysis. The halo-tolerant bacteria Staphylococcus gallinarum was also isolated and identified.