2008 Volume 10 Issue 1 Pages 10-14
The efficacy of low-energy, compact electron beam (EB) treatment for the surface sterilization of plastic container was studied. Electron energy of 150 keV, the lowest energy studied in applied research, was used in this experiment. The inactivation of spores of Bacillus pumilus ATCC 27142 was successfully demonstrated. Two microbiological methods, direct counting and fractional outgrowth, were used to measure the electron beam kill effectiveness for doses ranging from 3 kGy to 25 kGy. The resultant log-linear survival curve showed that the D10 value of B. pumilus is 1.4 kGy. This value is in good agreement with other researchers' results using EB and/or gamma irradiation. Extrapolation of the linear regression model from the survival curve also indicated that approximately 9 kGy was sufficient for a 6-log reduction. This was confirmed by the fractional outgrowth testing at the 12 kGy dose. This work demonstrates that low-energy EB is a novel in-line, room temperature method for sterilization of drug containers used in aseptic filling. The process is a viable alternative to the traditional in-house methods that employ ethylene oxide, steam, or hydrogen peroxide, and eliminates the need for chemicals or process water and the costs associated with their disposal. Cost, logistic and process validation issues associated with off-site sterilization methods such as high energy EB or gamma irradiation are also avoided.