Sampling should be done as close as possible to the critical area in Grade A environments, but without posing any risk to the process and sampling itself. To do both has been a long-standing dilemma, and often requires a specialized approach using technologies such as single use.
The frequency of viable sampling has received an almost revolutionary renewal in the Annex 1 draft. Chapter 9.25 indicates that sampling must be frequent and use a combination of methods. This leaves the decision to the manufacturer as to the methodology and data best-suited to the sampling point. At the moment, manufacturers tend to avoid multiple samplings of operators in order to prevent contamination build-up and the subsequent risk to the process and products. A possible solution is the implementation of more sampling techniques that do not leave residuals, such as swabs over contact plates.
Viable sampling should be performed continuously during routine process monitoring, as stated in Chapter 9.27. It will no longer be acceptable to have only small, snapshot sampling. This concept was applied in the 2008 version for “non-viable” counts and has now been expanded into “viable” counts, creating some short-term challenges for manufacturers. Continuous data generation can only be achieved by either real-time methods or long-term, traditional viable sampling that is quasi-continuous. The right combination of methods will become critical in the decision-making process.
Download the full paper for a more in-depth analysis of microbiological monitoring aspects for viable and non-viable contamination.