The durability of the bactericidal effect of supercritical CO_2 bubbling on E. coli bacteria

摘要

The durability of the bactericidal effect of supercritical CO_2 bubbling (the SC-CO_2 treatment) on E. coli bacteria during storage at 37°C was investigated. In model water samples containing 10~6 and 1O_2 CFU/ml, the number of survival E. coli cellsafter the SC-CO_2 treatment increased gradually during storage for 3 days and eventually equaled the number of non-treated E. coli cells. Also, after model water samples containing 10~6,10~7 or 10~8 CFU/ml of E. coli cells were sterilized completely bySC-CO_2 and autoclaving, we added 10~6 CFU/ml of E. coli cells and stored the samples for 3 days at 37°C. The number of added cells in both model water samples contained 10~8 CFU/ml killed E. coli cells treated with the SC-CO_2 and autoclave increased 10~4 fold, whereas the number of E. coli cells decreased in distilled water. The number of added cells in the model water sample contained 10~7 CFU/ml killed E. coli cells increased 10 fold. However, number of added cells in model water contained 10~6 CFU/ml cells decreased 10 fold. From these results, we concluded that the number of E. coli cells that survive SC-CO_2 treatment increased due to ingesting the killed E. coli cells as nutrition.