Kirby RM, Davies R. Survival of dehydrated cells of Salmonella typhimurium LT2 at high temperatures.
THE JOURNAL OF APPLIED BACTERIOLOGY 1990;
68:241-6. [PMID:
2187845 DOI:
10.1111/j.1365-2672.1990.tb02570.x]
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Abstract
Cells of Salmonella typhimurium LT2 were dehydrated on hydrophobic membranes (Millipore FGLP2500) placed in a controlled atmosphere chamber held at 57% equilibrium relative humidity (ERH) and 37 degrees C. Dehydration for 48 h under the above conditions increased the heat resistance of Salm. typhimurium LT2 when measured as the surviving fraction after a heat challenge of 135 degrees C for 30 min. Results also showed that little or no death occurred during heat challenges of 1 h at temperatures of up to 100 degrees C. The survival of Salm. typhimurium LT2 was measured as the ability to form colonies on solid media tryptone soy broth plus 1.2% agar (TSBA) after 24 h at 37 degrees C. Incorporation of sodium pyruvate, at a concentration of (TSBA) after 24 h at 37 degrees C. Incorporation of sodium pyruvate, at a concentration of 0.2% into the recovery medium, did not enhance the recovery of heated Salm. typhimurium LT2. Dehydrated cells of S. typhimurium LT2 showed a triphasic death curve. Increasing the period of dehydration from 48 h to 34 d, reduced initial numbers due to die off but did not alter the shape of the subsequent survival curve.
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