Isolation and identification of specific spoilage from low-salinity pickled turnip

The spoilage organisms in low-salinity pickled turnip during storage or circulation period were isolated and identified in this experiment. Seven bacteria strains and two yeasts obviously different in colony morphology were screened out following the traditional microbial culture and separation ways. Gram stain was conducted on bacterial strains, and DNA were extracted from the pure culture of bacterium and yeast. The 16 S rDNA and26 S rDNA of D1/D2 sequence gene sequencing were amplified. PCR products were sequenced and the results were identified and compared with the closest known sequences from NCBI, five bacteria were closed to Bacillus genera, one bacteria was closed to Lysinibacillus genera, two bacterias were closed to Candida genera, one bacteria was similar to a reported uncultured bacterium. By phylogenetic analysis, X5 share 97% similarity to Lysinibacillus sphaericus. The other strains shared 99%¹00% similarity to Bacillus sp., Bacillus subtilis, Bacillus megaterium, Bacillus boroniphilus, Lysinibacillus sphaericus, Bacillus gibsonii, Uncultured bacterium, Candida pararugosa, Candida zemplinina. It was speculated that the presence of bacillus and candida might be the major reason for spoilage of low-salinity pickled turnip through physiological, biochemical characteristic and analysis of corruption.