Document Detail

Salmonella spp. are affected by different levels of water activity in closed microcosms.
MedLine Citation:
PMID:  11464270     Owner:  NLM     Status:  MEDLINE    
Controlling water activity (a(w)) can significantly impact the growth of Salmonella in poultry litter and manure - a phenomenon that was studied quantitatively using two common serotypes of Salmonella. The quantitative effect of changes in levels of a(w) on Salmonella populations was determined using inoculated, frosted glass rectangles placed in closed chambers (microcosms). Glass rectangles with known concentrations of Salmonella enteritidis and S. brandenburg were placed in microcosms maintained at an a(w) level of 0.893 for 24 h at room temperature (RT) and then transferred to other microcosms maintained at the same temperature but with higher a(w) levels (0.932 and 0.987). Salmonella populations on the slides were quantified at 4, 18, 24, and 48 h. Slightly elevated levels of a(w) (<0.1, i.e., 10% equilibrium relative humidity) for 24 h resulted in a 100-fold increase in counts of Salmonella. The data also suggested that in vitro adaptation to dry environments may occur when the organisms are exposed to alternating levels of relatively high and low (0.987 and 0.893) levels of a(w). Any increased tolerance of Salmonella to reduced levels of a(w) could be the result of physico-chemical changes in the organism due to selective environmental pressure, formation of a protective biofilm, and/or entry into a dormant state. Results from this study are compatible with those from previously reported on-farm surveys, reinforcing the contention that maintaining a(w) below 0.85 in and around litter/manure surfaces in poultry or livestock bedding areas may be a critical factor in safe production of food.
C L Eriksson de Rezende; E T Mallinson; A Gupte; S W Joseph
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of industrial microbiology & biotechnology     Volume:  26     ISSN:  1367-5435     ISO Abbreviation:  J. Ind. Microbiol. Biotechnol.     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-07-20     Completed Date:  2002-06-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9705544     Medline TA:  J Ind Microbiol Biotechnol     Country:  England    
Other Details:
Languages:  eng     Pagination:  222-5     Citation Subset:  IM    
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
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MeSH Terms
Colony Count, Microbial
Feces / microbiology
Manure / analysis,  microbiology*
Salmonella / growth & development*,  isolation & purification
Salmonella enterica / growth & development,  isolation & purification
Salmonella enteritidis / growth & development,  isolation & purification
Time Factors
Water / metabolism*
Reg. No./Substance:
0/Manure; 7732-18-5/Water

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

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