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Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk

Non-thermal processing of milk can potentially reduce nutrient loss, and a low-temperature-high-pressure (LTHP) treatment is considered as a promising alternative to thermal treatment, attracting considerable attention in recent years. The effect of LTHP treatment (−25 °C, 100–400 MPa) on the phase...

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Autores principales: Li, Yifan, Zheng, Zhuoyun, Zhu, Songming, Ramaswamy, Hosahalli S., Yu, Yong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760655/
https://www.ncbi.nlm.nih.gov/pubmed/33255959
http://dx.doi.org/10.3390/foods9121742
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author Li, Yifan
Zheng, Zhuoyun
Zhu, Songming
Ramaswamy, Hosahalli S.
Yu, Yong
author_facet Li, Yifan
Zheng, Zhuoyun
Zhu, Songming
Ramaswamy, Hosahalli S.
Yu, Yong
author_sort Li, Yifan
collection PubMed
description Non-thermal processing of milk can potentially reduce nutrient loss, and a low-temperature-high-pressure (LTHP) treatment is considered as a promising alternative to thermal treatment, attracting considerable attention in recent years. The effect of LTHP treatment (−25 °C, 100–400 MPa) on the phase transition behavior of frozen milk was evaluated. The lethal and injured effects of different pressures and cycle numbers on E. coli in frozen milk were studied by using selective and non-selective enumeration media. Results from the gathered transient time–temperature–pressure data showed that pressures over 300 MPa could induce a phase transition from Ice I to Ice III. The treatment at −25 °C and 300 MPa could achieve a lethal effect similar to the two-cycle treatment of 400 MPa at room temperature. This meant that LTHP conditions can lower the operating pressure by at least 100 MPa or reduce the operation from two cycle to one cycle. Increasing the number of pressure cycles enhanced the lethal effects, which was not additive, but resulted in a transformation of part of the injured cells into dead cells. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) provided direct evidence for the breakdown of cell membrane and cell walls by phase transitions. Combined with a designed internal cooling device, the LTHP process can be expected to be a more attractive alternative to non-thermal processing for the dairy industry.
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spelling pubmed-77606552020-12-26 Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk Li, Yifan Zheng, Zhuoyun Zhu, Songming Ramaswamy, Hosahalli S. Yu, Yong Foods Article Non-thermal processing of milk can potentially reduce nutrient loss, and a low-temperature-high-pressure (LTHP) treatment is considered as a promising alternative to thermal treatment, attracting considerable attention in recent years. The effect of LTHP treatment (−25 °C, 100–400 MPa) on the phase transition behavior of frozen milk was evaluated. The lethal and injured effects of different pressures and cycle numbers on E. coli in frozen milk were studied by using selective and non-selective enumeration media. Results from the gathered transient time–temperature–pressure data showed that pressures over 300 MPa could induce a phase transition from Ice I to Ice III. The treatment at −25 °C and 300 MPa could achieve a lethal effect similar to the two-cycle treatment of 400 MPa at room temperature. This meant that LTHP conditions can lower the operating pressure by at least 100 MPa or reduce the operation from two cycle to one cycle. Increasing the number of pressure cycles enhanced the lethal effects, which was not additive, but resulted in a transformation of part of the injured cells into dead cells. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) provided direct evidence for the breakdown of cell membrane and cell walls by phase transitions. Combined with a designed internal cooling device, the LTHP process can be expected to be a more attractive alternative to non-thermal processing for the dairy industry. MDPI 2020-11-26 /pmc/articles/PMC7760655/ /pubmed/33255959 http://dx.doi.org/10.3390/foods9121742 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Li, Yifan
Zheng, Zhuoyun
Zhu, Songming
Ramaswamy, Hosahalli S.
Yu, Yong
Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title_full Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title_fullStr Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title_full_unstemmed Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title_short Effect of Low-Temperature-High-Pressure Treatment on the Reduction of Escherichia coli in Milk
title_sort effect of low-temperature-high-pressure treatment on the reduction of escherichia coli in milk
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760655/
https://www.ncbi.nlm.nih.gov/pubmed/33255959
http://dx.doi.org/10.3390/foods9121742
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