Analysis And Identification Of Food-borne Pathogens By MALDI-TOF Mass Spectrometry

Common food-borne pathogens are the important reason for food poisoning, which are closely associated with many human diseases and resulted in serious threat for people health and economic loss. Rapid, reliable detection of food-borne pathogens and effective prevention or control of pathogen infection are always objective of microbiologist and relevant researchers. MALDI-TOF mass spectrometry is mostly applied in field of chemical and life science, as a powerful tool for detection and identification of bio-molecules like peptide and protein, while it is used for analysis and identification of microorganisms.This thesis is focused on discrimination and identification of food-borne pathogens by using MALDI-TOF mass spectrometry. Firstly, E.coliO157:H7 was used as type strain to examine affections of different culture conditions, different matrix, and different pretreatment on protein mass spectra. A conducted method for analysis and identification of the food-borne pathogens was established. And then, this method was applied to discriminate five different genus of food-borne pathogens, such as listeria spp., Salmonella spp., E.coli O157:H7and DH5a, Enterobacter sakazakii, Staphyloccocus aureus, respectively. The results showed that, the different genus, species, serotype and strains used in this study could be distinguished and identified according to their specific mass spectra in the range of m/z 2000-15000 Da. The repeated results of the same sample and different batches of culture have proved the reproducibility of the MALDI-TOF analysis. Based on the established method and mass spectra results, a primary food-borne pathogens database was build. MALDI-TOF mass spectrometry can be used for rapid, accurate and sensitive discrimination and identication of food-borne pathogens, showing the useful significances.