Environmental Monitoring Programme is essential for evaluation of clean room contamination by known with different techniques are Settle plate , Air Sampling ,Contact plate method. In that Settle plate method is the most important one for determine the contamination levels in clean grades.
Settle Plate Method:
In Environmental Monitoring programme Settle Plate method is also known Passive Air Monitoring . In this method Soya been Casin Digestive Agar(SCDA) 90 mm plates are used for sampling . Passive Air Sampling is performed in clean room grades i.e. A,B,C,D exposure of SCDA Plates for 4 hrs .after exposure SCDA Plates need to incubate at 20- 25 degree centigrade for 72 hrs after incubation Periods SCDA plates transferred into 30-35 degree centigrade for 48 hrs. After incubation period count the number of colonies using by colony counter .
Ex: Location: SPM 16 – 47 cfu /4 hrs
Effectiveness of recovery rate from SCDA Plates in different time intervals:
In this study we need to know the how correlation between the hours of exposure and recovery rate of organisms in clean room monitoring . Initially study was conducted for ten different location in controlled Microbiology laboratory area, SCDA plates( 90mm) expose in particle location in controlled area in different time interwall up to 2 hr, 4 hr, 6hr, and 8 hrs ,after exposure these plates incubated in incubator at 20-25 0c for 72 hrs after transfer SCDA plates into 30-350c for 48 hrs .After incubation count the colonies under colony counter.
Microbiology
Laboratory Controlled Area Grade-C Location
|
02/06/20
Cfu/2 hr
|
03/06/20
Cfu/4 hr
|
04/06/20
Cfu/6 hr
|
04/06/20
Cfu/8hr
|
PSP01
|
25
|
38
|
29
|
18
|
PSP02
|
26
|
39
|
27
|
19
|
PSP03
|
36
|
42
|
35
|
26
|
PSP04
|
38
|
41
|
34
|
27
|
PSP05
|
18
|
31
|
27
|
21
|
PSP06
|
35
|
42
|
28
|
15
|
PSP07
|
34
|
39
|
29
|
21
|
PSP08
|
28
|
34
|
24
|
11
|
PSP09
|
29
|
31
|
22
|
13
|
PSP10
|
19
|
28
|
21
|
9
|
Alert
Level
|
45
|
45
|
45
|
45
|
Action
Level
|
50
|
50
|
50
|
50
|
Summary and Conclusion
From the above data summarises that the number of colonies are gradually decreases from 4 hrs exposure to 8 hr exposure due to over time exposure of SCDA plates leads to dryness and formation of a thick layer on the plate inhibits the growth of colonies and get false positive result. The above conclusion is clearly states that 2 to 4hr time best form environmental monitoring in clean rooms and controlled environment.
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