In situ methods for identification and typing for applications in food microbiology

In situ rRNA hybridization for idenfication of pathogenic bacteria has been developed for use in food samples. The application involves direct use on bacteria connected with meats, and possible consequences of stress treatments relevant for the food industry have been investigated. An important problem in relation to these investigations is to be able to distinguish between live and dead cells, a problem that is difficult to solve since there are no safe death criteria for bacteria. One of the technical challenges in the project has been to develop a method for detection of mRNA in single cells, to identify mRNAs with relevance for the distinction of dead from live cells, and to apply this approach to food samples. In the project, a method involving in situ PCR in single cells has been developed, which will be useful for mRNA detection in a broad spectrum of applications.