Document Detail

The effects of growth temperature and growth phase on the inactivation of Listeria monocytogenes in whole milk subject to high pressure processing.
MedLine Citation:
PMID:  17173999     Owner:  NLM     Status:  MEDLINE    
The aim of this study was to explore the effect of a wide range of growth temperatures, growth phases and plating media on the inactivation of Listeria monocytogenes by high pressure processing (HPP). In part one, L. monocytogenes was grown to mid-stationary phase at 4, 15, 25, 35 or 43 degrees C, inoculated into whole UHT milk at approximately 10(7) CFU/ml and high pressure processed at 400 MPa at room temperature (20-25 degrees C). Afterward, the HPP milk was plated on Tryptic Soy Yeast Extract Agar (TSYEA) and Modified Oxford Agar (MOX) to determine the degree of injury. For part two, cells were grown to mid-exponential, late-exponential or mid-stationary phase at 15 or 43 degrees C and processed in the same way. Time to reach a 5-log reduction was determined and data were analysed by ANOVA. The results from part one showed that both growth temperature and plating medium had a significant effect (P < 0.001) on the inactivation of stationary phase L. monocytogenes by HPP. Tukey's pairwise comparisons revealed that the effects of all temperatures, except 35 and 43 degrees C, were significantly different (P < 0.05). Cells grown at 15 degrees C were most sensitive to HPP, followed by cells grown at 4, 25 or 35 degrees C, with cells grown at 43 degrees C appearing to be the most resistant. Inactivation of cells grown at 4, 15 or 25 degrees C followed first order kinetics, whereas cells grown at 35 or 43 degrees C displayed non-linear inactivation kinetics due to tailing. In part two, both growth phase and plating medium had significant effects on the inactivation (P < or = 0.001) of L. monocytogenes by HPP. Cells grown at 15 degrees C to mid-stationary phase were the most pressure-resistant when tested on both media, and were significantly more resistant (P < 0.05) than cells grown at the same temperature to the other two phases of growth. There was no significant difference between mid- and late-exponential phase cells grown at 15 degrees C. When cells were grown at 43 degrees C, mid-exponential phase cells were significantly more sensitive (P < 0.05) than either late-exponential or mid-stationary phase cells, with no difference between late-exponential or mid-stationary phase cells. It was postulated that membrane composition, stationary phase proteins and/or stress proteins may affect pressure resistance.
Melinda M Hayman; Ramaswamy C Anantheswaran; Stephen J Knabel
Related Documents :
3263319 - Is rapid proliferation in b centroblasts linked to somatic mutation in memory b cell cl...
10487919 - Saccharomyces cerevisiae colony growth and ageing: biphasic growth accompanied by chang...
22262689 - The spermatogonial stem cell niche in the collared peccary (tayassu tajacu).
9146729 - Cell density downregulates dna synthesis and proliferation during osteogenesis in vitro.
15110849 - Differential effects of synthesized 2'-oxygenated chalcone derivatives: modulation of h...
17555439 - Defining candida albicans stationary phase by cellular and dna replication, gene expres...
15248029 - Synergistic killing of human leukemia cells by antioxidants and trichostatin a.
14613219 - Effect of silicon rubber crosslink density on fibroblast cell behavior in vitro.
23448299 - Morphological distribution of μ chains and cd15 receptors in colorectal polyp and aden...
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-12-14
Journal Detail:
Title:  International journal of food microbiology     Volume:  115     ISSN:  0168-1605     ISO Abbreviation:  Int. J. Food Microbiol.     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-03-13     Completed Date:  2007-05-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8412849     Medline TA:  Int J Food Microbiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  220-6     Citation Subset:  IM    
Department of Food Science, The Pennsylvania State University, 202 Food Science Building, University Park, PA 16802, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Analysis of Variance
Colony Count, Microbial
Consumer Product Safety
Food Contamination / prevention & control*
Food Microbiology
Hydrostatic Pressure*
Listeria monocytogenes / growth & development*
Milk / microbiology*

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

Previous Document:  Characterization of integrons and tetracycline resistance determinants in Aeromonas spp. isolated fr...
Next Document:  Evaluation of Chenopodium ambrosioides oil as a potential source of antifungal, antiaflatoxigenic an...