Isolation and Preliminary Identification of Specific Spoilage Organisms from Traditional Soybean Products White Bean Curd and Bean Curd

The spoilage organisms in white bean curd and bean curd during storage period were isolated and identified in this experiment.Nineteen strains obviously different in morphology were screened out,and the gram staining and their physical and chemical characteristic were identified using the method of pure culture.DNA were extracted from the pure culture of bacterium and yeast,and amplified the 16S rDNA and 26S rDNA;PCR products were sequenced and the results were identified and compared with the closest known sequences from NCBI to determine the various bacteria and yeast respective genus.The pure culture of mould were dyed to review the conidium morphology to indentify the genus of the strains.Results indicated that the common dominant spoilage organisms in the white bean curd and bean curd were Staphylococcus caseolyticus,Bacillus subtilis,Acinetobacter johnsonii,Pediococcus pentosaceus;Pichia guilliermondii,Trichosporon cutaneum;Penicillium cyclopium,Penicillium toxicarum Miyake.In addition,Candida zeylanoides was specific organism in white bean curd,and Pseudomonas luteola and Trichosporon cutaneum in bean curd.