Viable Air Monitoring

Scientist in a clean room reading out a contact plate after testing the air for viable microorganisms.

Microbial air monitoring is the process of sampling and analyzing microbial contamination in the air. It is an important step in quality control of manufacturers in the pharmaceutical, cosmetics, food and beverage industries. Air quality plays a critical role in aseptic environments, cleanrooms and production areas, where microorganisms in the air are a potential risk for cross-contamination of raw materials and final products.

Active Microbial Air Monitoring

The need for efficient active air monitoring is growing, as regulations and standards for pharmaceutical, food, and beverage products are increasing. In these industries the quality of the production environments is directly linked to the finished products’ quality. Active air monitoring determines the number of viable organisms per cubic meter of air, and is part of continuous routine testing during the manufacturing process.

Microbial air samplers actively impact microorganisms onto the agar surface of a culture medium, which is then incubated, and the results are analyzed by enumerating the microorganisms that have grown on the culture medium. If the test result is positive for presence of microbial contamination in the air, especially in critical areas, it is followed by an identification test to determine the genus of the microorganism.

Passive Microbial Air Monitoring

Passive air sampling is an important complement to active air monitoring methods. This method is used to measure the levels of contamination that have dropped from the air onto surfaces. Settle plates (also known as sedimentation plates or settling plates) allow for continuous, semi-quantitative determination of microbial contamination in the air.

Settle plates are placed openly in the test area for a specific period of time, allowing microorganisms to drop from the air and grow on the culture media. To enhance microbial growth, the media plate is placed in an incubator that provides optimal growth conditions. After a specified period of time, the cultures grown are enumerated and if needed identified using an identification test.


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