Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> 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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MDPI AG
2020-11-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/9/12/1742 |
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| author | Yifan Li Zhuoyun Zheng Songming Zhu Hosahalli S. Ramaswamy Yong Yu |
| author_facet | Yifan Li Zhuoyun Zheng Songming Zhu Hosahalli S. Ramaswamy Yong Yu |
| author_sort | Yifan Li |
| collection | DOAJ |
| 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 <i>E. coli</i> 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. |
| first_indexed | 2024-03-10T14:33:22Z |
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| id | doaj.art-cca86b2f50b048d6ad184cc1ae374d5d |
| institution | Directory Open Access Journal |
| issn | 2304-8158 |
| language | English |
| last_indexed | 2024-03-10T14:33:22Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
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| series | Foods |
| spelling | doaj.art-cca86b2f50b048d6ad184cc1ae374d5d2023-11-20T22:24:07ZengMDPI AGFoods2304-81582020-11-01912174210.3390/foods9121742Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in MilkYifan Li0Zhuoyun Zheng1Songming Zhu2Hosahalli S. Ramaswamy3Yong Yu4College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, ChinaCollege of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, ChinaCollege of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, ChinaDepartment of Food Science, McGill University, 21111 Lakeshore Road, St-Anne-de-Bellevue, QC H9X 3V9, CanadaCollege of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, ChinaNon-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 <i>E. coli</i> 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.https://www.mdpi.com/2304-8158/9/12/1742low-temperature-high-pressure (LTHP)<i>Escherichia coli</i>milknon-thermal processingmicrobial inactivationfood safety |
| spellingShingle | Yifan Li Zhuoyun Zheng Songming Zhu Hosahalli S. Ramaswamy Yong Yu Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk Foods low-temperature-high-pressure (LTHP) <i>Escherichia coli</i> milk non-thermal processing microbial inactivation food safety |
| title | Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk |
| title_full | Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk |
| title_fullStr | Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk |
| title_full_unstemmed | Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk |
| title_short | Effect of Low-Temperature-High-Pressure Treatment on the Reduction of <i>Escherichia coli</i> in Milk |
| title_sort | effect of low temperature high pressure treatment on the reduction of i escherichia coli i in milk |
| topic | low-temperature-high-pressure (LTHP) <i>Escherichia coli</i> milk non-thermal processing microbial inactivation food safety |
| url | https://www.mdpi.com/2304-8158/9/12/1742 |
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