More on microbial sampling

To the Editor:

I enjoyed the article in CleanRooms on airborne microbial sampling methods. It was an excellent summary of current industry standards, which are constantly in flux. I would like to see a follow-up article on surface microbial sampling methods. This is also a very key activity in contamination control in cleanroom environments.

I have experience with all the sampling methods discussed in the article. I enjoyed using the Sartorious MD8 when I was working for a client in the U.K. In actual practice, I did not notice that it performed any better than the Biotest RCS or RCS + 1 normally used for that type of sampling. Introduction of a new method into a licensed facility is a long, expensive process. Each method has its inherent strengths and weaknesses and the type of methodology can be tailored to the type of environmental sampling condition encountered in a particular facility.

Companies tend to have a lot invested in their particular choice of method(s). I have my own favorites. As long as the methods have been established, the company should stick with them for as long as possible, just for the sake of continuity and to relieve any anxiety from regulatory agencies picking up on changes to microbial monitoring programs. Change, while inevitable, is not popular.

Tod E. Ransdell

Sr. Validation Specialist

Sanofi Diagnostics Pasteur, Inc.

Redmond, WA