Formation and Control of the Viable but Non-culturable State of Foodborne Pathogen Escherichia coli O157:H7

作者：Li, Yanmei; Huang, Teng-Yi; Ye, Congxiu; Chen, Ling; Liang, Yi; Wang, Kan^*; Liu, Junyan^*

来源：Frontiers in Microbiology, 2020, 11: 1202.

DOI：10.3389/fmicb.2020.01202

• E. coli O157
• H7
• VBNC
• food system
• control
• detection

As a common foodborne pathogen,Escherichia coliO157:H7 produces toxins causing serious diseases. However, traditional methods failed in detectingE. coliO157:H7 cells in the viable but non-culturable (VBNC) state, which poses a threat to food safety. This study aimed at investigating the formation, control, and detection of the VBNC state ofE. coliO157:H7. Three factors including medium, salt, and acid concentrations were selected as a single variation. Orthogonal experiments were designed with three factors and four levels, and 16 experimental schemes were used. The formation of the VBNC state was examined by agar plate counting and LIVE/DEAD(R)BacLight (TM) bacterial viability kit with fluorescence microscopy. According to the effects of environmental conditions on the formation of the VBNC state ofE. coliO157:H7, the inhibition on VBNC state formation was investigated. In addition,E. coliin the VBNC state in food samples (crystal cake) was detected by propidium monoazide-polymerase chain reaction (PMA-PCR) assays. Acetic acid concentration showed the most impact on VBNC formation ofE. coliO157:H7, followed by medium and salt concentration. The addition of 1.0% acetic acid could directly killE. coliO157:H7 and eliminate its VBNC formation. In crystal cake, 25, 50, or 100% medium with 1.0% acetic acid could inhibit VBNC state formation and killE. coliO157:H7 within 3 days. The VBNC cell number was reduced by adding 1.0% acetic acid. PMA-PCR assay could be used to detectE. coliVBNC cells in crystal cake with detection limit at 10(4)CFU/ml. The understanding on the inducing and inhibitory conditions for the VBNC state ofE. coliO157:H7 in a typical food system, as well as the development of an efficient VBNC cell detection method might aid in the control of VBNCE. coliO157:H7 cells in the food industry.

• 单位
  汕头大学; 广州医学院; 中山大学