RELATIVE HUMIDITY AND THE KILLING OF BACTERIA II

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

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, depen...

Relative humidity and the killing of bacteria. I. Observations on Escherichia coli and Micrococcus lysodeikticus.

Some observations on the ability of washed Escherichia coli and Mficrococcus lysodeikticus to form colonies when plated after having been freeze-dried and exposed to water vapor in vacuo will be presented in this paper. Serratia marcescens treated in this manner is rapidly killed within a rather narrowly limited range of relative humidities around 90 per cent (Monk and McCaffrey, 1957). It was ...

The Lethal Effect of Relative Humidity on Air-borne Bacteria

The viability of pneumococcus, Type I, sprayed into the atmosphere from a liquid suspension was measured as a function of the relative humidity. When broth, saliva, or 0.5 per cent saline solution is employed as the suspending medium, a very high mortality rate is observed at relative humidities in the vicinity of 50 per cent. However, at humidities above or below this value the microorganisms ...

Effects of temperature and relative humidity on the response of phaseolus vulgaris to salinity

Effect of Relative Humidity

HIMMELFARB, PHILIP (University of Massachusetts, Amherst), HAMED M. EL-BISI, R. B. READ, JR., AND WARREN LITSKY. Effect of relative humidity on the bactericidal activity of propylene oxide vapor. Appl. Microbiol. 10:431-435. 1962.-Because of the low toxicity of its breakdown product, propylene oxide (PO) vapor will play an increasingly important role in the preservation of foods. It is therefor...