Analysis of survival rates and cellular fatty acid profiles of Listeria monocytogenes treated with supercritical carbon dioxide under the influence of cosolvents
- Authors
- Kim, Soo Rin; Park, Hee Jung; Yim, Do Seong; Kim, Hee Tack; Choi, In-Geol; Kim, Young Heon
- Issue Date
- 9월-2008
- Publisher
- ELSEVIER SCIENCE BV
- Keywords
- supercritical carbon dioxide; Listeria monocytogenes; food-borne pathogen; inactivation of microorganisms; sterilization
- Citation
- JOURNAL OF MICROBIOLOGICAL METHODS, v.75, no.1, pp.47 - 54
- Indexed
- SCIE
SCOPUS
- Journal Title
- JOURNAL OF MICROBIOLOGICAL METHODS
- Volume
- 75
- Number
- 1
- Start Page
- 47
- End Page
- 54
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/122809
- DOI
- 10.1016/j.mimet.2008.04.012
- ISSN
- 0167-7012
- Abstract
- In the present study, we identified several process variables that significantly affect the efficiency of supercritical carbon dioxide inactivation of the food-borne pathogen Listeria monocytogenes. Treatment with SC-CO2 completely disabled the colony-forming activity of the cells (8-log reduction) within specific treatment time (10-50 min), pressure (80-150 bar), and temperature ranges (35-45 degrees C). Microorganism inactivation rates increased proportionally with pressure and temperature, but the inactivation rate decreased significantly when cells were suspended in phosphate-buffered saline rather than in physiological saline. Additionally, when the microbial cell suspension was 80-100% (w/w) of water, the SC-CO2-mediated reduction in CFU ml(-1) was 4-8 log higher at the same treatment conditions than in typical cell suspensions (a water content of 800-4000% [w/w]) or dry preparations that had only 2-10% (w/w) of water. The addition of a fatty acid, oleic acid, decreased the effectiveness of the microbial inactivation by SC-CO2, but the addition of a surfactant, sucrose monolaurate, increased the effectiveness. Therefore, cosolvents for SC-CO2, including water, a fatty acid, and a surfactant in this study, were found to greatly influence on the inactivation effectiveness. The extraction of cellular substances, such as nucleic acid- and protein-like materials and fatty acids, was monitored by spectrophotometry and GC/MS and increased with SC-CO2 treatment time. Additionally, using scanning and transmission electron microscopies, we investigated morphological changes in the SC-CO2-treated cells. The effects of the variables we have described herein represent a significant contribution to our current knowledge of this method of inactivating food-borne pathogens. (C) 2008 Elsevier B.V. All rights reserved.
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