Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i>
<i>Salmonella enterica</i> represents a diverse group of pathogens commonly associated with food contamination including red meat. Even though pre- and post-harvest cleaning and sanitization procedures are widely implemented at meat processing plants to mitigate the hazard, <i>S. e...
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MDPI AG
2025-01-01
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| Series: | Foods |
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| author | Zachariah Vice You Zhou Sapna Chitlapilly Dass Rong Wang |
| author_facet | Zachariah Vice You Zhou Sapna Chitlapilly Dass Rong Wang |
| author_sort | Zachariah Vice |
| collection | DOAJ |
| description | <i>Salmonella enterica</i> represents a diverse group of pathogens commonly associated with food contamination including red meat. Even though pre- and post-harvest cleaning and sanitization procedures are widely implemented at meat processing plants to mitigate the hazard, <i>S. enterica</i> cells may escape the process by colonizing, on contact, surfaces in the form of a biofilm that functions as an aggregated microbial community to facilitate mutual protection, antimicrobial resistance, proliferation and dissemination. Biofilm development is a complex process that can be affected by a variety of factors including environmental temperature. We developed methods using scanning electron microscopy and confocal microscopy with a novel image analysis software tool to investigate the temperature influence on <i>S. enterica</i> cell colonization and biofilm formation by directly visualizing and comparing the biofilm matrix’s morphological differences under various temperatures. Cocktails of <i>S. enterica</i> strains belonging to serovars, commonly isolated from meat samples, were applied to develop biofilms on a stainless steel surface at 7, 15, or 37 °C. Results of the microscopy analysis showed that as temperature increased, better-defined biofilm structures with extracellular polymeric structures (EPS) could be identified. However, <i>S. enterica</i> colonization and aggregated bacterial biomass were clearly observed at the low temperature (7 °C) as well. These results demonstrate that the environmental temperature significantly contributes to <i>S. enterica</i> biofilm formation as the higher temperatures encourage bacterial active proliferation and biofilm maturation leading to the development of well-pronounced structures, while the lower temperature may promote cell attachment but, meanwhile, limit the EPS biosynthesis and biofilm maturation. Our study indicates that the mature <i>S. enterica</i> biofilms formed under favorable conditions may protect the pathogens with the well-developed 3-demensional (3D) structure against routine treatment. Furthermore, the low temperatures commonly maintained at meat plants are not able to effectively prevent <i>S. enterica</i> colonization and biofilm formation since at such temperatures there could still be colonized biomass that can contaminate the products. Therefore, the temperature effect on pathogen colonization and biofilm development should be taken into consideration while evaluating hygiene standards and sanitization procedures at the processing facilities. |
| format | Article |
| id | doaj-art-f69174546ad342b88cfe5ad78f24e67f |
| institution | Kabale University |
| issn | 2304-8158 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Foods |
| spelling | doaj-art-f69174546ad342b88cfe5ad78f24e67f2025-01-24T13:33:05ZengMDPI AGFoods2304-81582025-01-0114226810.3390/foods14020268Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i>Zachariah Vice0You Zhou1Sapna Chitlapilly Dass2Rong Wang3Department of Animal Science, Texas A&M University, College Station, TX 77845, USACenter for Biotechnology, University of Nebraska–Lincoln, Lincoln, NE 68588, USADepartment of Animal Science, Texas A&M University, College Station, TX 77845, USAU.S. Meat Animal Research Center, Agriculture Research Service (ARS), U.S. Department of Agriculture (USDA), Clay Center, NE 68933, USA<i>Salmonella enterica</i> represents a diverse group of pathogens commonly associated with food contamination including red meat. Even though pre- and post-harvest cleaning and sanitization procedures are widely implemented at meat processing plants to mitigate the hazard, <i>S. enterica</i> cells may escape the process by colonizing, on contact, surfaces in the form of a biofilm that functions as an aggregated microbial community to facilitate mutual protection, antimicrobial resistance, proliferation and dissemination. Biofilm development is a complex process that can be affected by a variety of factors including environmental temperature. We developed methods using scanning electron microscopy and confocal microscopy with a novel image analysis software tool to investigate the temperature influence on <i>S. enterica</i> cell colonization and biofilm formation by directly visualizing and comparing the biofilm matrix’s morphological differences under various temperatures. Cocktails of <i>S. enterica</i> strains belonging to serovars, commonly isolated from meat samples, were applied to develop biofilms on a stainless steel surface at 7, 15, or 37 °C. Results of the microscopy analysis showed that as temperature increased, better-defined biofilm structures with extracellular polymeric structures (EPS) could be identified. However, <i>S. enterica</i> colonization and aggregated bacterial biomass were clearly observed at the low temperature (7 °C) as well. These results demonstrate that the environmental temperature significantly contributes to <i>S. enterica</i> biofilm formation as the higher temperatures encourage bacterial active proliferation and biofilm maturation leading to the development of well-pronounced structures, while the lower temperature may promote cell attachment but, meanwhile, limit the EPS biosynthesis and biofilm maturation. Our study indicates that the mature <i>S. enterica</i> biofilms formed under favorable conditions may protect the pathogens with the well-developed 3-demensional (3D) structure against routine treatment. Furthermore, the low temperatures commonly maintained at meat plants are not able to effectively prevent <i>S. enterica</i> colonization and biofilm formation since at such temperatures there could still be colonized biomass that can contaminate the products. Therefore, the temperature effect on pathogen colonization and biofilm development should be taken into consideration while evaluating hygiene standards and sanitization procedures at the processing facilities.https://www.mdpi.com/2304-8158/14/2/268<i>Salmonella enterica</i>biofilmsconfocal microscopyscanning electron microscopy |
| spellingShingle | Zachariah Vice You Zhou Sapna Chitlapilly Dass Rong Wang Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> Foods <i>Salmonella enterica</i> biofilms confocal microscopy scanning electron microscopy |
| title | Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> |
| title_full | Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> |
| title_fullStr | Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> |
| title_full_unstemmed | Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> |
| title_short | Microscopic Analysis of Temperature Effects on Surface Colonization and Biofilm Morphology of <i>Salmonella enterica</i> |
| title_sort | microscopic analysis of temperature effects on surface colonization and biofilm morphology of i salmonella enterica i |
| topic | <i>Salmonella enterica</i> biofilms confocal microscopy scanning electron microscopy |
| url | https://www.mdpi.com/2304-8158/14/2/268 |
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