Environments free of microbial contamination are an essential requirement in manufacturing of sterile pharmaceutical products, medical devices and even in laboratories engaged in testing of microbial parameters on such products. To start with you should understand the difference between sterile and aseptic. Though both the terms are often used as synonyms but they are different. Sterile refers to complete absence of microorganisms whereas aseptic is used for measures adopted for prevention of presence of microorganisms in the regulated space
In reality it is not possible to remove microbial contamination completely when human workers are present as in spite of humans wearing protective wear and face masks. Humans are always releasing microorganisms to some extent. Complete sterility cannot be achieved in a clean room but measures can be taken to monitor and control microorganisms in clean rooms.
One practical approach is to monitor the compressed air for freedom from microbial impurities before it is allowed to enter clean room area and laboratory workers wear full body protective clothing and face masks when working inside such zones.
Compressed air microbial presence can be monitored effectively with the help of SAS Super Pinocchio II for petri plates. The device has been ordered and is expected to arrive shortly in our Bangalore laboratory. Once put in operation it will make it possible to conduct microbiological count in our Microbiological laboratory under near sterile conditions. It is a convenient to handle device and offers several advantages, namely,
- No external power supply requirement as pressure in compressed air line is only required to operate the system.
- Light weight and easily portable for use in different areas.
- IQ/OQ and PQ protocols are available.
- Parts can be easily dismantled using plastic or paper sterilization bags and can be easily reassembled after autoclaving. Alternately, sterilization can also be done using ionizing radiation.
Sampling procedure for airborne microorganisms
The compressed air supply is monitored using impactation on a petri dish filled with a nutrient agar.
Slit to agar air sampler
The compressed air is directed through a standardized slit below which is placed a slowly revolving petri dish containing the nutrient agar. The microorganisms present impact the agar and are allowed to grow inside the incubator.
The cover of the unit has perforated openings of pre-determined size. The compressed air enters through the sieve, whose size is progressively decreased before impacting the medium in the petri dish.
The flow meter on the system regulates the inflow of compressed air at100 litres/min. The sampling timed for 10 minutes to obtain the standard volume of 1000 litre or 1 cu m which is necessary for obtaining the optimum sensitivity. At the end of the sampling period the plate is kept inside the incubator for the purpose of CFU counting.
Once installed the device will help maintain the optimum sterile conditions for improving the reliability of microbiological parameters in our laboratory.