Development of a detection system for genetically modified microorganisms from starter and protective cultures

In this work a system for the detection of genetically modified microorganisms is presented, that may be applied for an all-purpose, resp. non-specific identification of starter and protective cultures, which are modified by means of genetic engineering.The detection system is based on an equalization of the genome of the strain, that might be genetically modified with the genome of a near relative reference-strain, which is not genetically modified. For that purpose Representational Difference Analysis (RDA) is used, a combination of subtractive hybridisation and suppression PCR. The generated strain-specific DNA fragments are isolated by two-dimensional polyacrylamide gelelectrophoresis. Their DNA sequences are compared with resources of DNA data banks. The detection system was developed and proved using the model organisms Lactobacillus sake and Penicillium nalgiovense. It is suitable for the examination of all microorganisms, which are applied for the processing and conservation of foods. The method permits the detection of genetically modified microorganisms on condition that they contain two or three genetic elements from foreign species. Its main advantage: there is no necessity of knowledge about the DNA sequences of the foreign genetic elements