Extracellular pH decline introduced by high pressure carbon dioxide is a main factor inducing bacteria to enter viable but non-culturable state

Dong Yang; Yongtao Wang; Liang Zhao; Lei Rao; Xiaojun Liao

doi:10.1016/j.foodres.2021.110895

Extracellular pH decline introduced by high pressure carbon dioxide is a main factor inducing bacteria to enter viable but non-culturable state

Food Res Int. 2022 Jan:151:110895. doi: 10.1016/j.foodres.2021.110895. Epub 2021 Dec 15.

Authors

Dong Yang¹, Yongtao Wang¹, Liang Zhao¹, Lei Rao², Xiaojun Liao³

Affiliations

¹ College of Food Science and Nutritional Engineering, China Agricultural University, National Engineering Research Center for Fruit & Vegetable Processing, Key Laboratory of Fruit & Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-thermal Processing, Beijing 100083, China.
² College of Food Science and Nutritional Engineering, China Agricultural University, National Engineering Research Center for Fruit & Vegetable Processing, Key Laboratory of Fruit & Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-thermal Processing, Beijing 100083, China. Electronic address: rao.lei@cau.edu.cn.
³ College of Food Science and Nutritional Engineering, China Agricultural University, National Engineering Research Center for Fruit & Vegetable Processing, Key Laboratory of Fruit & Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-thermal Processing, Beijing 100083, China. Electronic address: liaoxjun@cau.edu.cn.

PMID: 34980417
DOI: 10.1016/j.foodres.2021.110895

Abstract

High pressure carbon dioxide (HPCD) has been used in food processing as a non-thermal pasteurization technology. However, the potential of HPCD to induce viable but non-culturable (VBNC) cells limits its application. The objective of this study was to explore the roles of extracellular pH of 3 (pH_ex3) and high pressure (HP) of HPCD during VBNC induction and the underlying molecular mechanism. By using the model organism Escherichia coli O157:H7, we found that the combined effects of pH_ex3 and HP could mimic the effect of HPCD for VBNC induction. Further investigation of the individual effect of pH_ex3 and HP on VBNC induction revealed that pH_ex3 could induce a higher proportion of VBNC cells with a slower induction rate compared with HPCD, whereas HP was unable to induce VBNC formation. Notably, the cells treated by pH_ex3 and HPCD had similar morphological changes, and VBNC cells induced by pH_ex3 and HPCD had similar stress resistance characteristics. These results strongly indicated that pH_ex3 introduced by HPCD was a main factor for VBNC induction. Additionally, we found that HP played the role in accelerating VBNC formation in the process of HPCD treatment. Transcriptomic analysis revealed 85, 263 and 529 differentially expressed genes (DEGs) for HP-, pH_ex3- and HPCD-treated cells compared with untreated ones. 59 DEGs shared by pH_ex3 and HPCD treatment might be responsible for VBNC induction, and they were mainly involved in cellular transport and localization.

Keywords: Acid; E. coli O157:H7; High pressure; High pressure carbon dioxide; Viable but non-culturable.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon Dioxide*
Escherichia coli O157*
Food Handling
Hydrogen-Ion Concentration

Substances

Carbon Dioxide