Evaluation of bacterial flora during the ripening of Kedong sufu, a typical Chinese traditional bacteria-fermented soybean product

Background Kedong sufu is a typical bacteria-fermented sufu in China. Isolation and identification of the autochthonous bacteria involved would allow the design of specific starters for this speciality. The purpose of the present study was to evaluate the bacterial flora during the ripening of Kedong sufu using polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and culturing. Results In terms of bacterial diversity, 22 strains were isolated and identified and 27 strains were detected by DGGE. Regarding bacterial dynamics, the results of culturing and PCR-DGGE exhibited a similar trend towards dominant strains. Throughout the fermentation of sufu, Enterococcus avium, Enterococcus faecalis and Staphylococcus carnosus were the dominant microflora, while the secondary microflora comprised Leuconostoc mesenteroides, Staphylococcus saprophyticus, Streptococcus lutetiensis, Kocuria rosea, Kocuria kristinae, Bacillus pumilus, Bacillus cereus and Bacillus subtilis. Conclusion This study is the first to reveal the bacterial flora during the ripening of Kedong sufu using both culture-dependent and culture-independent methods. This information will help in the design of autochthonous starter cultures for the production of Kedong sufu with desirable characteristic sensory profiles and shorter ripening times.