High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment
High Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they ma...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-11-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/10/12/2940 |
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| author | Justyna Nasiłowska Aleksandra Kocot Paulina Natalia Osuchowska Barbara Sokołowska |
| author_facet | Justyna Nasiłowska Aleksandra Kocot Paulina Natalia Osuchowska Barbara Sokołowska |
| author_sort | Justyna Nasiłowska |
| collection | DOAJ |
| description | High Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they may proliferate in food during storage. This study was undertaken to characterize the extent of sublethal injuries induced by HHP (300–500 MPa) on <i>Escherichia coli</i> and <i>Listeria inncua</i> strains. The morphological changes were evaluated using microscopy methods such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Epifluorescence Microscopy (EFM). The overall assessment of the physiological state of tested bacteria through TEM and SEM showed that the action of pressure on the structure of the bacterial membrane was almost minor or unnoticeable, beyond the <i>L. innocua</i> wild-type strain. However, alterations were observed in subcellular structures such as the cytoplasm and nucleoid for both <i>L. innocua</i> and <i>E. coli</i> strains. More significant changes after the HHP of internal structures were reported in the case of wild-type strains isolated from raw juice. Extreme condensation of the cytoplasm was observed, while the outline of cells was intact. The percentage ratio between alive and injured cells in the population was assessed by fluorescent microscopy. The results of HHP-treated samples showed a heterogeneous population, and red cell aggregates were observed. The percentage ratio of live and dead cells (L/D) in the <i>L. innocua</i> collection strain population was higher than in the case of the wild-type strain (69%/31% and 55%/45%, respectively). In turn, <i>E. coli</i> populations were characterized with a similar L/D ratio. Half of the cells in the populations were distinguished as visibly fluorescing red. The results obtained in this study confirmed sublethal HHP reaction on pathogens cells. |
| first_indexed | 2024-03-10T04:08:13Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2304-8158 |
| language | English |
| last_indexed | 2024-03-10T04:08:13Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Foods |
| spelling | doaj.art-5ff5995c9121469a870ca39c2ce265bb2023-11-23T08:16:33ZengMDPI AGFoods2304-81582021-11-011012294010.3390/foods10122940High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic AssessmentJustyna Nasiłowska0Aleksandra Kocot1Paulina Natalia Osuchowska2Barbara Sokołowska3Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, 01-142 Warsaw, PolandDepartment of Immunology and Food Microbiology, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, 10-748 Olsztyn, PolandBiomedical Engineering Centre, Institute of Optoelectronics, Military University of Technology, 01-142 Warsaw, PolandWacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, 01-142 Warsaw, PolandHigh Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they may proliferate in food during storage. This study was undertaken to characterize the extent of sublethal injuries induced by HHP (300–500 MPa) on <i>Escherichia coli</i> and <i>Listeria inncua</i> strains. The morphological changes were evaluated using microscopy methods such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Epifluorescence Microscopy (EFM). The overall assessment of the physiological state of tested bacteria through TEM and SEM showed that the action of pressure on the structure of the bacterial membrane was almost minor or unnoticeable, beyond the <i>L. innocua</i> wild-type strain. However, alterations were observed in subcellular structures such as the cytoplasm and nucleoid for both <i>L. innocua</i> and <i>E. coli</i> strains. More significant changes after the HHP of internal structures were reported in the case of wild-type strains isolated from raw juice. Extreme condensation of the cytoplasm was observed, while the outline of cells was intact. The percentage ratio between alive and injured cells in the population was assessed by fluorescent microscopy. The results of HHP-treated samples showed a heterogeneous population, and red cell aggregates were observed. The percentage ratio of live and dead cells (L/D) in the <i>L. innocua</i> collection strain population was higher than in the case of the wild-type strain (69%/31% and 55%/45%, respectively). In turn, <i>E. coli</i> populations were characterized with a similar L/D ratio. Half of the cells in the populations were distinguished as visibly fluorescing red. The results obtained in this study confirmed sublethal HHP reaction on pathogens cells.https://www.mdpi.com/2304-8158/10/12/2940HHPfoodborne pathogensSEMTEMEFM |
| spellingShingle | Justyna Nasiłowska Aleksandra Kocot Paulina Natalia Osuchowska Barbara Sokołowska High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment Foods HHP foodborne pathogens SEM TEM EFM |
| title | High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment |
| title_full | High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment |
| title_fullStr | High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment |
| title_full_unstemmed | High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment |
| title_short | High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment |
| title_sort | high pressure induced sublethal injuries of food pathogens microscopic assessment |
| topic | HHP foodborne pathogens SEM TEM EFM |
| url | https://www.mdpi.com/2304-8158/10/12/2940 |
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