Environmental monitoring and certification of both viable and nonviable particulates and contaminants present in the cleanroom environment is a program designed to demonstrate the control of viable (living microorganisms) and non-viable particles in critical areas. These areas include clean-rooms for drug fill/finish, formulation tank rooms, laminar flow hoods, biological safety hoods, isolators, glove boxes, molding machines, kit assembly lines, Intravenous (IV) compounding areas and sterile packaging.
Viable monitoring refers to testing for the detection and enumeration of bacteria, yeast and mold. It includes the monitoring of personnel, air and area surfaces for microbial contamination. Viable counts provide metrics on the potential for contamination of a company's products as well as demonstrating the veracity that a clean room is functioning as designed and being properly maintained. Surface and air monitoring exhibit the asepsis of the product manufacturing operation.
Non-viable environmental monitoring which is a reference for particle counts measured by a laser counter.
Companies who have their clean room facilities monitored do so to ensure their desired/required quality standards are met. The areas that are sampled in a manufacturer's clean room include:
1. Personnel – Personnel are the biggest source of contamination in clean areas. Personnel harbor millions of bacteria, carrying them with them everywhere they go. Gowning is the most effective way to protect the cleanroom environment from ourselves. To asses the effectiveness of the gowning program personnel may be monitored on a regular basis for viable counts. Personnel monitoring employs contact plates to assess microbial contamination of clean room personnel.
2. Air - the air in a clean room is controlled and Monitored on a regular basis (e.g., daily, weekly, quarterly) for particle counts, viable counts, temperature and humidity. HEPA filters are used to control the viable and non-viable particulate counts within the air. HEPA filters have the capability to filter out particulates down to 0.3 micr on in size. These filters usually run continuously at a calibrated flow rate in order to maintain the required air quality within the room. Humidity is usually kept at a low level in order to help prevent the proliferation of microbes within the room such as bacteria and mold, which tend to prefer damp conditions in order to replicate.
3. Surfaces - (including floors, walls, equipment, etc.) are cleaned and monitored on a regular basis for viable counts by using specially designed contact plates that contain a growth medium called Trypticase Soy Agar (TSA) and Sabouraud Dextros Agar (SDA). The TSA is a growth medium designed for bacteria and the SDA and a growth medium designed for mold and yeast. TSA and SDA are typically incubated at different temperatures, TSA at 30-35 C which is mainly the optimal growing temperature for most environmental bacteria, and 20-25 C which is the optimal growing temperature for most mold and yeast species.
There are differences across the major guidance documents regarding the limits for both viable and non-viable particulates. The ISO 14644-1 deals entirely with non-viable particulate sizes for various clean-room.