FIG. 1.

Pressure resistance and membrane damage in exponential-phase cells of E. coli strains C9490 (●), H1071 (▴), and NCTC 8003 (■). (a) Survivors after treatment at different pressures for 8 min; (b) osmotic responses of pressure-treated cells measured as the increase in OD of cell suspensions placed in 0.75 M NaCl; (c) permeability of pressure-treated cells to PI, measured as an increase in fluorescence relative to that of untreated cells. PI was added after pressure treatment. Viable counts following treatments at pressures above 200 MPa were below the limits of detection (50 CFU/ml).