Wednesday 21 December 2016

Passive Air Sampling

  • Passive air means inactive air.(inactive air sampling).
  • Air flow is not disturbed.
  • Is also called Settle plate method or sedimentation technique.
  • During this time particles are settle down on the media plate by gravitation force.
  • This method is still widely used as a simple and inexpensive way.
  • Each operational shift expose plates 4-5 hours period. (As per USP General chapter 797).
  • At least 1 cubic meter (m3) air should be tested.
  • Incase of critical manufacturing operation extended for more than 8 hours expose one more set of plates.
  • Collect all the plates after completion of 4 hrs exposure time.
  • For Exmple less than 4 hours exposures, to be establish the In-house limits, because all guidelines limits given CFU/ 4hours only.
  • After exposure close the lid and incubate the plates inversely.
  • Incubation temperature at 20-25° C have been used for 72 hours, next 30-35° C for 48 hours.
  • Lower incubation temperature encouraging for Fungal, mesophilic organisms  and slow growing organisms.
  • Higher incubation temperature encouraging for Bacteria.
  •  In this method Pre incubated 90 mm SCDA (Soybean Casein Digest Agar or Tryptic Soya Agar) with glycerol plates  is better for Passive air sampling.
  •        SCDA used for cultivation of wide variety of micro organisms in pharmaceutical procedure.
  • Glycerol prevent the media evaporation or dehydration.(Quantity of the glycerol depending upon the validation study).
  • The positive point of this method is that viable contamination could be checked for long hours.
  • But drawback is also there with this method as it could only check viable contamination which collect or deposit over the media plate during exposure hours.
  • So, location for plate exposure should be properly selected and justified based on the risk assessment studies.
  • Passive air sampling is 4/1/1 scheme. It means for 4 hour exposure, 1m above the floor, about 1 m away from walls.
  • After completion of incubation observe the count under colony counter.

What is the fumigation and fogging?

What is the fumigation and fogging?