Food Transgenic Crop Traceability System And Correlation Detection Technology

ObjectivesTo establish a comprehensive genetically modified (GM) crops tracing and reporting software system, which can be used to search for, collect and manage the information of GM crops timely. To explore the impact of different processing methods on DNA degradation and the performances of different DNA extraction methods. Finally, to produce a commercial kit screening for GM maize (MON810, Bt11, NK603,59122 and 1507) in foods.Methods1. GM crops traceability systemMicrosoft SQL Server 2000 System, Java language and hibernate were used to establish a database and an application. Information about existing GM crops was collected by referring to the literatures, databases, patent information and the documents of approval and regulatory from home and abroad, and was then added to the database and application.2. Detection techniqueThe samples were processed by heating (electromagnetic oven and microwave oven respectively). Four different methods (phenol/chloroform extraction, Genomic DNA Purification Kit, Mag-Bind DNA Kit and spin column) were used to extract the genomic DNA from the samples. The impact on DNA lengths by heating were examined and theβ-actin contents in the extracted DNA were measured.Ten primer sets for exogenous genes of the five varieties of maize were included in the GM corn fast screening kit, five for screening and five for fixing position. Two plasmids with the exogenous genes were used as the reference molecules to evaluate the validity of the PCR (polymerase chain reaction) analyses. In addition, we applied a result-judging application to quick positioning the variety of GM maize in the sample detected. Results1. GM crops traceability systemThe GM crops tracing and reporting software system includes 46 varieties of GM maize,7 GM rices,11 GM soybeans and 7 GM wheats. Over 30 exogenous genes sequences,400 marketing information,321 approval documents,215 nucleic acid-based methods,53 endogenous reference gene testing methods,39 protein-based methods,4 reference molecules and 18 endogenous reference genes of 4 species. Users registered could submit new information. Verified information would be updated instantly in this database.2. Detection techniqueThe concentrations of the heated fish decreased significantly compared to that of raw fish. The extraction methods with the higher DNA concentrations are phenol/chloroform extraction and Genomic DNA Purification Kit, and the lower ones are spin column and Mag-Bind DNA Kit.The detection using GM corn fast screening kit can be carried out by two steps, screening and fixing position. Exogenous genes were found out in GM maize but not in traditional maize. The lower limits of the primers are all below 0.1%. The probable variety of GM maize contained in testing samples can be told by result-judging application by inputting exogenous genes that are found out in samples.Conclusions1. GM crops traceability systemThe GM crops tracing and reporting software system provides an efficient tool of whole-course dynamic management for administration authority and a convenient query facility for users at large.2. Detection techniqueDNA could be degraded by heating. Therefore, the target fragments of DNA in food selected for DNA detection should be short. As for the extraction methods, Genomic DNA Purification Kit is efficient and safe for DNA extraction of processed food.The kit with the result-judging application and the reference molecules is considered to be a simple and reliable aid of screening for GM maize in processed foods, using a two-step polymerase chain reaction analysis for simultaneous qualitative detection of five varieties of GM maize in foods.