Starting later this year, A2C2 will begin a multi-part series on environmental bioburden testing for clean rooms and their relationships to setting alert and action limits both for environments and products. The articles by Gregg A. Mosley, lead instructor for the AAMI course, “Industrial Sterilization of Medical Devices”, will first focus on the meaning of the data collected by current techniques. Second, the issue of the relationship between environmental data from clean room manufachIring and the actual product attributes will be discussed, in addition to applicable alert and action limits. lastly, the sources of common contamination which allows ingress of organisms with unusual levels of resistance both for terminal product sterilization and routine facility sanitization will be discussed. The following are exceIpts relating some of the topics to be discussed:
‘The issue of the use of “settle plates” is identified in respected references and the passive capture of settling microbes represents one of the oldest measurement systems for collecting airborne microbes. One article stated, “Because of air turbulence and random particle settling, settling plates are not quite accurate”. This statement is simply not true. Settle plates measure exactly that phenomenon for which they are intended; the random settling of biologically active particles (BAPs). As will be shown, the relevance of settle plates corresponds directIy to the potential impact of BAPs on the process and product, while the relevance of active sample results is uncertain.
Settle plate measurements may be more relevant to assessing potential distribution of BAP’s on product than either surface or air sampling. Regardless of which method or combination of methods are employed, one conclusion is certain; each of the three methods measure different contaminating attributes and there is no direct correlation between any two as a general rule.
The use of active samplers is often implemented without due consideration of their potential impact, both on the sample itself and on the process and products. Active samplers should NEVER be hand held during the sampling process.
Companies often implement alert and action limits based only on the (environmental) biological sampling data. This may result in frequent alert and action responses because the data gathering sequence was too short.
The escape from this cycle is to float limits upward dynamically based on correlation of new environmental data with product data collected at the same time. This approach allows a two way street within which manufacturers can operate.
It should be noted that processes during which the product is wiped with 70% IP A (or another suitable disinfectant), especially just prior to final packaging, often produce product bioburden levels little related to environmental bioburden levels.
