Molecular Fingerprint Technology For Quality And Safety Supervision Of Thailand Jasmine Rice

In this paper, modern molecular techniques including RAPD, multplex PCR-CE-SSCP, 2DE, MALDI-TOF were applied in methodology research for Thailand jasmine rice authentication, storage quality detection and foodborne pathogen identification. The further standardization of these methods would promote official supervision of imported Thailand jasmine rice, protection of consumer's right and development of rice import and export trade.The first part was jasmine rice identification and purity detection. Totally 32 rice cultivars including reference cultivar (KDML105 and RD15) and representative non-jasmine rice cultivars were studied. RAPD fingerprint analysis demonstrated that phylogenetic relationship of the 32 samples was generally consistent with practical kinship. In order to simplify the method for routine detection at CIQ lab, two RAPD markers (R2-449 and R5-1107) were selected for which RAPD and SCAR methods were established. Thailand jasmine rice was identified by its recessive trait of the two markers. A serious of experiments proved that the method possess high resolution, good reproducibility and accuracy.The second part was about storage quality inspection. 2DGE was used to analyze 6 jasmine rice samples of different production year.The PMF of major peptide spots were analyzed and protein identiy were determined on the basis both of PMF and data in international rice proteomics database. The results showed that the chaning pattern of 2DE profiles were consistent with the crop year. Significant change between 2008 and 2007 corp year was observed, indicating high resolution of the method. Not only could the method be applied as a helpful complement of present standard for storage quality evaluation, but also reveal biological process during storage which is important informantion for rice production, processing and circulation.The third part was fast identification method for foodborne pathogens. Comapred to traditional microbiological identification method and routine PCR method, multiplex PCR-CE-SSCP was characterized as faster, higher throughput and more automatic. Here 16srRNA and gyrB gene based multiplex PCR-CE-SSCP system were established and DNA fingerprint data of 25 referrence strains was collected. Phylogenetic analysis showed that the taxonomy tree was generally consistent with traditionl taxamony relationship. Signal peak was identified by relative position to inner markers instead of retaining time and good reproducibility was proved. Considering the fact that newly emergent foodborne pathogen, E.sakasaki, was frequently found in infant formula rice powder, we further analyzed 42 E.sakasaki isoltates separated from food, the data of which was believed to be helpful for optimization of present detection method and for further research of E.sakasaki population in food.