The biocontainment of a high speed disc bowl centrifuge

Abstract

The containment of a high speed disc bowl centrifuge during normal operation has been examined using a mutant E. coli strain and a range of sampling devices to monitor the release of viable organisms. A discharge of a small amount of supernatant was used to provide a mimic of a release of a low number of organisms with a view to testing the sensitivity of the sampling systems used. Three sampling devices were used: settle plates, a slit sampler and an air filter sampler. These were all shown to be effective in the collection of viable organisms during the release under low pressure of 10 ml of supernatant (equivalent microbial count to 0.02 ml fermentation broth). Three runs carried out under normal operation of the centrifuge showed no release of viable organisms. The prevention of a second source of release during disassembly and cleaning of the bowl was demonstrated to be possible by the ability to clean and steam sterilize in place. The consequences of such operations are discussed in terms of the use of high speed disc bowl centrifuges for the processing of organisms under various levels of containment.