Bp. Hills et al., WATER AVAILABILITY AND THE SURVIVAL OF SALMONELLA-TYPHIMURIUM IN POROUS SYSTEMS, International journal of food microbiology, 36(2-3), 1997, pp. 187-198
The survival of Salmonella Typhimurium LT2 in randomly packed beds of
glass beads, microporous silica particles and Sephadex microspheres is
examined. It is shown that the decrease in the percentage cell recove
ry in these porous materials at reduced water content is not correlate
d with the global water activity as determined by conventional vapour
pressure measurements but rather with the osmotic shock induced by the
sudden redistribution of water and air among the microscopic pores in
the matrix surrounding the cells. For this reason the bacterial survi
val and growth data correlates best with physical measurements, such a
s NMR and electrical conductivity, which are sensitive to the microsco
pic air-water distribution. The implications of this observation in fo
od safety and preservation are discussed. (C) 1997 Elsevier Science B.
V.