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Research Article

Determination of Heat Resistance of Exponential Phase Enterococcal Cells

Mushtaq Ahmad , David G. Smith and S. Mahboob
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The heat resistance of exponential phase cells of environmental barley isolates Enterococcus faecium BAR 1 and a hospital isolate Enterococcus faecalis MI 2 grown at 37 or 45 was determined at 55, 60 and 62.5 ° C for 30 min. From the survival curves, the decimal reduction times (D-values) were determined. Cells grown at 45° C showed higher D-values. It was determined that the exponential phase cells grown at 45 were more resistant to heat than the heat resistance of cells grown at 37° C. The cells of both isolates were found resistant to heat treatment at 55, 60 and 62.5 as compared with the control in which cells were grown at 37° C and treated at 62.5° C.

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  How to cite this article:

Mushtaq Ahmad , David G. Smith and S. Mahboob , 2003. Determination of Heat Resistance of Exponential Phase Enterococcal Cells. Journal of Biological Sciences, 3: 340-346.

DOI: 10.3923/jbs.2003.340.346


1:  Aguirre, M. and M.D. Collins, 1993. Lactic acid bacteria and human clinical infection. J. Applied Bacteriol., 75: 95-107.
Direct Link  |  

2:  Ahmad, M., D.G. Smith and S. Mahboob, 2002. Determination of the heat shock response in Etnerococcus faecium and Enterococcus faecalis. Int. J. Agric. Biol., 4: 231-234.

3:  Bunning, V.K., R.G. Crowford. J.T. Tierney and J.T. Peeler, 1992. Thermo-tolerance of heat shocked Listeria monocytogenes in milk exposed to higher temperature short time pasteurization. Applied Environ. Microbiol., 58: 2096-2098.
Direct Link  |  

4:  Gordon, C.L.A. and M.H. Ahmad, 1991. Thermal susceptibility of Steptococcus faecium strains isolated from Frankfurters. Can. J. Microbiol., 37: 609-612.
Direct Link  |  

5:  Jorgensen, F., B. Panaretou, P.J. Stephens and S. Knochel, 1996. Effect of Pre-and post-heat shock temperature on the persistence of Thermo-tolerance and heat shock induced proteins in Listeria monocytogenes. J. Applied Bacteriol., 80: 216-224.
Direct Link  |  

6:  Kaye, D.M.D., 1982. Enterococci: Biologic and epidemiological characteristics and in vitro susceptibility. Arch. Int. Med., 142: 2006-2009.
Direct Link  |  

7:  Knudtson, L.M. and P.A. Hartman, 1992. Enterococci in pork processing. J. Food Prot., 55: 1-5.

8:  Lindquist, S., 1986. The heat shock response. Annu. Rev. Biochem., 55: 1151-1191.
PubMed  |  

9:  Mackey, B.M and C. Derrick, 1990. Heat shock protein synthesis and Thermo-tolerance in Salmonella typhimurium. J. Applied Bacteriol., 69: 373-383.
Direct Link  |  

10:  Magnus, C.A., A.R. McCurdy and W.M. Ingledew, 1988. Further studies on the thermal resistance of Streptococcus faecium and Streptococcus faecalis in pasteurized ham. Can. Inst. Food Sci. Tech., 21: 209-212.
Direct Link  |  

11:  Patchett, R.A., N. Watson, P.S. Fernandez and R.G. Kroll, 1996. The effect of temperature and growth rate on the susceptibility of Listeria monocytogenes to environmental stress conditions. Lett. Applied Microbiol., 22: 121-124.

12:  Perez, B.S., P.L. Lorenzo, M.L. Garcia, P.E. Hernandez and J.A. Ordonez, 1982. Heat resistance of enterococci. Milchwissenschaft, 37: 724-726.

13:  Smith, B.J. and M.P. Yaffe, 1991. Uncoupling thermo-tolerance from the induction of heat shock proteins. Proc. Nat. Acad. Sci. USA., 88: 11091-11094.
Direct Link  |  

14:  Thian, T.S. and P.A. Hartman, 1981. Genetamicin-Thallous carbonate medium for isolation for faecal streptococci from foods. Applied Environ. Microbiol., 41: 724-728.

15:  Webber, L.A., 1992. Relationship of heat shock proteins and induced thermal resistance. Cell Prolif., 25: 101-113.
Direct Link  |  

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