Issue 9, 2022

Inactivation mechanisms of Escherichia coli O157:H7 and Salmonella enterica by free residual chlorine

Abstract

The sub-cellular mechanisms by which residual free chlorine (FC) inactivates E. coli O157:H7 and S. enterica in the absence of organic matter was investigated. The average removal rates for E. coli were 38–99% after a 1 min exposure to 0.12–0.5 mg L−1 FC, while that of S. enterica were 10–50% after exposure to 0.5–2.0 mg L−1 FC. Chlorination caused significant membrane structural damage and reduced membrane potential. Low FC levels or short exposure times had a modest impact on S. enterica. Cell metabolic activity decreased over time for all initial FC levels, and with increasing FC levels at each time point. Total ATP levels increased in the first minute post-chlorination, while the intracellular ATP levels decreased with increasing FC levels and exposure time, likely due to ATP leakage. The depolarized E. coli density reached a plateau after the first 2 min at FC ≥ 0.5 mg L−1 while that of S. enterica took 5 min to reach a plateau even at FC ≥ 1 mg L−1, indicating their ability to withstand chlorination. Residual FC levels are sufficient to induce damage to cellular organelles and compromise their survival, and the mechanism of injury depends on FC levels and exposure time.

Graphical abstract: Inactivation mechanisms of Escherichia coli O157:H7 and Salmonella enterica by free residual chlorine

Supplementary files

Article information

Article type
Paper
Submitted
24 Mei 2022
Accepted
04 Ago 2022
First published
05 Ago 2022

Environ. Sci.: Water Res. Technol., 2022,8, 2006-2018

Author version available

Inactivation mechanisms of Escherichia coli O157:H7 and Salmonella enterica by free residual chlorine

M. D. Abnavi, T. Larimian, P. Srinivasan, D. Munther and C. R. Kothapalli, Environ. Sci.: Water Res. Technol., 2022, 8, 2006 DOI: 10.1039/D2EW00382A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements