| Effect of environmental stresses on the mean and distribution of individual cell lag times of Escherichia coli O157:H7. | |
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MedLine Citation:
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PMID: 16815581 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The effect of starvation, heat or acid stress on duration of individual cell lag time (tau) and standard deviation (SD) of tau was investigated using Escherichia coli O157:H7. Cells were stressed by exposure to acid (pH 3.5), heat (50 degrees C), or starvation in either glucose-free mineral medium (MOPS), tryptic soy broth (TSB) or Luria broth (LB). Stressed cells were then diluted into wells of a Bioscreen plate to obtain single cells per well. Replicate time to detection (td) values were obtained using the Bioscreen and used to calculate the tau and SD. Significant (P< or =0.05) increases in tau over untreated controls were found for the following treatments: 14 days in acid; 2 h of heating; 3 days starvation in MOPS; and 2 days starvation in either TSB or LB. The largest increase in tau was >2-fold from 2.5 to 5.6 h observed with the heat treatment. MOPS starvation was more detrimental to the cells than was acid treatment over the same time period. A significant increase in SD was found with 21 days acid treatment, and 2 days starvation in either TSB or LB. No significant increase in SD was found for MOPS starvation or heat treatment. Lognormal, Gamma, ExtremeValue and Weibull distributions were fitted to the tau data using BestFit. The results suggest that the Lognormal distribution is suitable for fitting tau data from either stressed or unstressed cells. |
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Authors:
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Yaqin Li; Joseph A Odumeru; Mansel Griffiths; Robin C McKellar |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-07-11 |
Journal Detail:
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Title: International journal of food microbiology Volume: 110 ISSN: 0168-1605 ISO Abbreviation: Int. J. Food Microbiol. Publication Date: 2006 Aug |
Date Detail:
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Created Date: 2006-07-31 Completed Date: 2006-09-18 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8412849 Medline TA: Int J Food Microbiol Country: Netherlands |
Other Details:
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Languages: eng Pagination: 278-85 Citation Subset: IM |
Affiliation:
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Laboratory Service Division, University of Guelph, 95 Stone Road West, Guelph, Ontario, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Colony Count, Microbial Culture Media / chemistry* Environment Escherichia coli O157 / growth & development* Food Microbiology Hot Temperature* Hydrogen-Ion Concentration* Kinetics Mathematics Models, Biological* Models, Statistical Predictive Value of Tests |
| Chemical | |
Reg. No./Substance:
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0/Culture Media |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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