Determination, statistics, and analysis of initially contaminated microorganisms on medical devices treated by γ-radiation sterilization

In order to investigate the influence of initially contaminated microorganisms on medical devices for treatment by γ-radiation sterilization, 620 batches of products collected from more than 50 manufactures in Jiangsu, Zhejiang, Shanghai and so on have been inspected by use of ISO11737-1 2006 sterilization of medical devices-microbiological methods-Part 1. The results show that the product batches share is 7.9%, 43.5%, 26.0%, 18.2 % and 4.4% with an average bioburden of ≤1.5, 1.5~100, 100~1000, 1000~10000 and 10000 cfu/piece, respectively. These data are helpful to the dose decision for γ-radiation sterilization and quality stability of medical product.