Linked Life Data

18206772

Source:http://linkedlifedata.com/resource/pubmed/id/18206772

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-1-21
pubmed:abstractText
The majority of published studies on the adaptive heat or acid tolerance response of Listeria monocytogenes have been performed with a single strain exposed to a single adaptation treatment; however, in food ecosystems, microorganisms commonly exist as multi-species communities and encounter multiple stresses, which may result in "stress hardening". Therefore, the present study evaluated the adaptive responses to heat (52, 57 and 63 degrees C) or lactic acid (pH 3.5) of a 10-strain composite of L. monocytogenes meat and human isolates at stationary phase, following exposure to combinations of osmotic (10% NaCl), acidic (pH 5.0 with HCl) and thermal (T; 46 degrees C) stresses, sequentially or simultaneously within 1.5h, in tryptic soy broth with 0.6% yeast extract (TSBYE). All treatments induced adaptive responses on L. monocytogenes at 57 degrees C, while no such cross-protection was observed at 52 and 63 degrees C. Survivor curves at 57 degrees C appeared convex with profound shoulders determined by a Weibull model. The highest thermotolerance was observed after combined exposure to acid and heat shock (pH-T), followed by exposure to osmotic shock, and by the combination of osmotic with heat shock (NaCl-T). Regarding acid tolerance, prior exposure to low pH, pH-T, or a combination of NaCl, pH and T resulted in a marked increase of resistance to pH 3.5, showing concave inactivation curves with tails at higher levels of survivors (log(10)CFU ml(-1)) than the control cultures. The sequence of exposure to sublethal stresses did not affect the thermotolerance of L. monocytogenes, whereas simultaneous exposure to most multiple stresses (e.g., NaCl-pH-T, NaCl-T and NaCl-pH) resulted in higher survivors of L. monocytogenes at pH 3.5 than exposure to the same stresses sequentially. The results indicate that combinations and sequences of sublethal hurdles may affect L. monocytogenes acid and heat tolerance, especially in acidic environments with mild heating or in low moisture environments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1095-9998
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
294-303
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Heat and acid tolerance of Listeria monocytogenes after exposure to single and multiple sublethal stresses.
pubmed:affiliation
Department of Animal Sciences, Center for Meat Safety and Quality, Colorado State University, 1171 Campus Delivery, Fort Collins, CO 80523-1171, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't