Effective Heat Sterilization in CO2 Incubators

Contamination control and elimination have beena major concern in cell culture laboratories for over100 years. Though other technologies have beendeveloped over this period for instruments, devices,and textiles, dry heat sterilization has emerged asthe most useful contamination eliminationtechnology for equipment chamber surfaces. A dryheat sterilization cycle has now been validated forThermo Electron Corporation's Steri-Cycle® CO2Incubators. This sterilization cycle readily eliminatesthe vegetative microorganisms, as well as persistentfungal spores, of concern in cell culture laboratories.Cycle time is based on validation procedures usingcommercially available spore suspensions calibratedfor dry heat resistance. The spores were inoculatedonto chamber wall, door, and gasket materials.The inoculated materials were exposed at theminimum temperature (the coolest, and therefore leastlethal) observed in the incubator as determined byextensive mapping studies.The validated cycle time was based on the longestaverage time required to achieve a six-log reduction ofthe most resistant spore batch tested. This exposuretime was then more than doubled to establish asterilization cycle that exceeds the requirements formedical instruments.