Microbiological Environmental Monitoring plays an important role in pharmaceutical and medical device manufacturing to demonstrate the state of control of the facilities from a contamination control standpoint (1). Based on regulatory requirements, environmental monitoring data is used for the qualification of cleanrooms. Whereas, routine environmental monitoring data trends are used to understand the operational quality of the cleanroom; the effectiveness of the cleaning and sanitization program of the facilities; the effectiveness of the air handling system; effectiveness of gowning and personnel behavior; flow of personnel, material and waste, microbial hotspots as well as it helps to determine the dominant microorganisms of any particular environments. In other words, environmental monitoring programs serve as an early warning system for microbiological hazards and a drift from environmental control (2).
In general, environmental monitoring is divided into viable and non-viable monitoring (3). Microbiological environmental monitoring falls in the viable monitoring and can be further divided into the following sample types: a. passive air sampling: settle plates; b. active air sampling: volumetric air sampler; c. surface samples: contact plates or swabs; d. personnel sampling: fingers, sleeves/other areas of gowns (1, 3). Looking closer at the microbiological environmental monitoring, it is evident that there are certain factors which play a critical role in the generation of meaningful data to ensure implementation of a value-added environmental monitoring program. Some of these factors are: microbiological culture media; incubation time and temperature; sampling technique; sampling methods, sample location; frequency of sampling; sampling volume, room condition for the sampling and the sampling personnel (technique). In addition, studies have demonstrated that traditional culture-based tests utilizing microbiological media can recover only 1% - 10% of the microorganisms actually present in any environmental sample (4).
A study by Amann et. al. indicated that cultivation-based methods represent <0.001 % of the total microbial life truly present (5). This becomes more critical for the pharmaceutical environments as microorganisms present within pharmaceutical operations (e.g.; water and gas systems, environmental samples) often are highly stressed due to the inhospitable environment and residual chemical agents. Microorganisms present can be viable but non culturable (VBNC) for several reasons such as not able to reproduce, have special nutritional requirements, slow grower, or that the culture media, incubation temperature and time is not optimal for recovery (15). The absence of recovery does not mean that the air or surface was clean and might give a false sense of cleanliness (15). This also suggests that trending of environmental monitoring data is more important than absolute numbers. All of these factors induce variability to the data generated. Going forward, there is an alternative way of performing microbial environmental monitoring.