Detection of VOCs in E. Coli Based on Gas Chromatography-Mass Spectrometry

Escherichia coli (E. coli) is a common bacteria that belongs to the family Enterobacteriaceae, which is a ubiquitous microorganism in the environment and human intestinal trac. E. coli is one of the common foodborne pathogens which is a highly diverse species that include numerous types and strains with distinctive characteristics. Many methods are used to detect E. coli at present. Volatile Organic Compounds (VOCs) are all kinds of organic compounds with boiling points ranging from 50 ℃ to 260 ℃ at room temperature. Solid-phase Microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) are the main methods to detect VOCs at present. In this paper, we firstly evaluated the relationship between culture days and activity of three different E. coli strains in the early stage and verified optimal incubation time of the strains for VOCs analysis. Then, we studied VOCs products of E. coli, E. coli BL21 (Escherichia coli BL21) and Extraintestinal Pathogenic Escherichia coli (ExPEC) under extraction conditions of 37 ℃ and 80 ℃ respectively, and screened out several iconic VOCs, which provided a theoretical basis for further detection.