Monday 28 February 2022

Material Transfer Into Aseptic Areas: Hierarchy Of Contamination Control


The presence of viable organisms and in particular bacterial spores in the Grade A environment presents a significant risk of contamination in aseptically prepared products and potential patient harm. In terms of risk terminology, the likelihood of product contamination is low, but the consequences are severe. This places a considerable emphasis upon transfer disinfection / decontamination. The method that was commonly used for this process was a standard transfer hatch (an interlocking device with no air supply) where items going in were (ideally) multi-wrapped and subject to manual disinfection (sometimes no more than ‘spray and pray,’ a slightly better process being the application of a sporicidal agent and wiping the surfaces of each item). This process has been improved by fitting localized air supplies (Grade A / ISO class 5 at rest), which is the minimum EU GMP Annex 1 requirement (as indicated in the 2020 draft)(3), and with the wider availability of decontamination chambers (which use bio-decontamination agents like hydrogen peroxide) (4). A commonality with each of these approaches is the application of a sporicide, with in aqueous or vapor form. The Technical Committee (CEN/TC 216 “Chemical disinfectants and antiseptics”) of the European Committee for Standardization has defined a sporicidal as a product which kills dormant bacterial spores of relevant test organisms under defined conditions.

However, despite some similarities there is a contamination control hierarchy with the different methods of transferring items into an aseptic area. If autoclaving is placed at the top (since it is a sterilization rather than a disinfection method), then it follows in order of increasing contamination risk:


  • ·         Autoclaving / depyrogenaton tunnels
  • ·         Automated cycle decontamination chambers.
  • ·         ‘Dynamic’ pass-through hatches with HEPA filtered air supply.
  • ·         ‘Static’ pass through chambers with no air supply.
  • ·         Personnel transferring items (e.g., via changing rooms).

This paper assesses the transfer disinfection process, the available technologies and critical bio-decontamination aspects, focusing on the important criteria for device assessment and operation.


Sandle, T.(2021) Material Transfer Into Aseptic Areas: Hierarchy Of Contamination Control, Journal of GxP Compliance, 25 (5):


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

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