Establishment and application of molecular quality control methods for standard strains for food inspection

Objective The molecular quality control methods were established and applied for the standard strains of food inspection.

Methods The different molecular methods, such as 16S rRNAgene sequence analysis, pulsed-field gel electrophoresis (PFGE), and multi locus sequence typing, were used for the molecular confirmation of the standard strains of food inspection used according to national food safety standards, and they were verified by the different batch strains.

Results The results obtained after 16S rRNA gene sequence alignment were consistent with the genus of the strain and the 16S rRNA gene sequences of different batch standard strains were identical; Sequence typing (ST) type of the standard strains were identified and the ST of different batch isolates were identical. The research on the method of PulseNet was exploded on the strains without the standard method to obtain the suitable condition of restrictive endonuclease and electrophoresis parameters. The methods were then used to establish molecular fingerprints of standard strains. The PFGE profile similarity of different batches was 100%.

Conclusion The molecular biology technology was applied on the quality control of the standard strains for the first time in this study. It hit the bottleneck of traditional quality control methods. The stability of the standard strains was assessed at the molecular level to ensure the stability and consistence of the standard strains in the food inspection process.