Sterilization period 
Carrier materials 
Result 
50 min 
PVDF from Millipore 
All positive in a total of 10 samples 

PS from Millipore 
All negative in a total of 10 samples 

PS from Nihon Pall 
All negative in a total of 10 samples 

PS from Sartorius 
All negative in a total of 10 samples 
20 min 
PS from Sartorius 
All positive in a total of 10 samples 

PS from Nihon Pall 
Two negative samples in 10 samples 

PC from Millipore 
Six negative samples in 10 samples 

PS from Millipore 
All negative in a total of 10 samples 
Sterilization condition:ozone gas concentration 3000ppm, relative humidity (RH)
80%, temperature 35^{°}C, microorganism G. stearothermophilus ATCC 7953,
2.4 x 10³ CFU/sheet PVDF: polyvinylidene difluoride, PS: polysulfone, PC:
polycarbonate 