EFFECT OF CONDITIONS ON THE BAROTOLERANCE OF ESCHERICHIA-COLI

The effects of both cultural and pressurizing conditions on the barotolerance of pressurized Escherichia coli were studied by monitoring survivors, injured cells, and release of UV-absorbing substances. An obvious effect of pressurization on E. coli appeared above 1,500 atm, and the survival rate greatly decreased above 1,800 atm. Barotolerance was not affected by medium composition for growth or by the presence of O-2, while it increased with the progress of growth stages. Cells grown at 44 degrees C were less tolerant. The pH value during the pressurization slightly influenced the barotolerance. Survival rate was greatly decreased by pressurization at 44 degrees C. Barotolerance increased with increasing osmotic pressure during the pressurization.