Document Detail


Analysis of survival rates and cellular fatty acid profiles of Listeria monocytogenes treated with supercritical carbon dioxide under the influence of cosolvents.
MedLine Citation:
PMID:  18565606     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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-CO(2) 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-CO(2)-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-CO(2), but the addition of a surfactant, sucrose monolaurate, increased the effectiveness. Therefore, cosolvents for SC-CO(2), 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-CO(2) treatment time. Additionally, using scanning and transmission electron microscopies, we investigated morphological changes in the SC-CO(2)-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.
Authors:
Soo Rin Kim; Hee Jung Park; Do Seong Yim; Hee Tack Kim; In-Geol Choi; Kyoung Heon Kim
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-05-16
Journal Detail:
Title:  Journal of microbiological methods     Volume:  75     ISSN:  0167-7012     ISO Abbreviation:  J. Microbiol. Methods     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-12     Completed Date:  2008-10-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8306883     Medline TA:  J Microbiol Methods     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  47-54     Citation Subset:  IM    
Affiliation:
School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
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MeSH Terms
Descriptor/Qualifier:
Carbon Dioxide / pharmacology*
Fatty Acids / metabolism*
Food Microbiology*
Food Preservation / methods*
Listeria monocytogenes / cytology,  drug effects*,  metabolism
Microbial Viability / drug effects*
Pressure
Solvents / pharmacology*
Temperature
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Solvents; 124-38-9/Carbon Dioxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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