Relative humidity and the killing of bacteria: the variation of cellular water content with external relative humidity or osmolality.

نویسندگان

  • J B BATEMAN
  • C L STEVENS
  • W B MERCER
  • E L CARSTENSEN
چکیده

The paper deals with the relationship betweeen the water content of washed Serratia marcescens and the thermodynamic activity of water, a,, over the range 0 < a, < 1.0. Two overlapping types of measurement are used: osmotic water exchange and water-vapour sorption. The data are given in terms of the equation w = Bm-' where w is water content, m is external osmolality (actual or effective, depending upon the technique used), B is a constant and r has values which can be interpreted in terms of the type of process involved : e.g. in the initial stages of osmotic dehydration, r of unity would indicate ideal solution behaviour; in the final stages of drying, any constant value of r would conform to an adsorption function like that of Halsey (1948). The data obtained by the two techniques used fall on a single curve with several zones including (a) non-ideal solution behaviour at high a,, ( b ) two intersecting ' co-operative adsorption ' zones at very low a,, and ( c ) a region of variable r where processes such as dissolution of small molecules and ' saturated ' swelling of interlinked polymeric structures are presumed to occur. It is thought that detailed interpretation of the unified water uptake curves would be valuable in understanding mechanisms of humidity-dependent loss of viability, in particular the zones of exceptionally rapid attenuation.

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عنوان ژورنال:
  • Journal of general microbiology

دوره 29  شماره 

صفحات  -

تاریخ انتشار 1962