DISINFECTANT EFFICACY TEST (BY SWABING METHOD)

1.0 PURPOSE :
To evaluate the bio-load in production area after disinfectant treatment.
2.0 SCOPE :
This is designed to establish and ensure the effectiveness of disinfectant to control the surface bio-load in production area.
3.0 RESPONSIBILITY :
QC Microbiologist in co-ordination with QA/Production
4.0 FREQUENCY :
Once in a year or as and when required.
5.0 PROCEDURE :
Preparation media and its composition refer SOP No. QC/MB/xx/xxx
Dilute the disinfectant using DM water to desired concentration..
Sampling Procedure:
Sample I
Swab an ear marked area (20 x 20 cm) before cleaning.
Rinse the swab in100ml of sterile water.
Sample II
Follow the cleaning procedure and wipe the surface with low concentration of disinfectant (ie 1% v/v solution dettol or phenyl solution).
Swab an earmarked area (20 x 20 cm) which has been cleaned. Rinse the swab in100ml of sterile water.
Sample III
Follow the cleaning procedure and wipe the surface with high concentration of disinfectant (ie 2 % v/v solution dettol or phenyl solution).
Swab an earmarked area (20 x 20 cm) which has been cleaned. Rinse the swab in100ml of sterile water.
On completion of sampling identify each flask with proper Status label indicating percentage disinfectant used and sampling date and bring to the microbiology department.
Collected samples should be tested within one hour of collection . It is permitted to hold samples at 2 to 8°C for a period of four hours before testing.
Method of testing:
Test to be carried out in clean room under laminar flow only.
Follow the membrane filtration technique.
After completion of filtration remove the membrane filter
Using sterile forceps and scissors cut into two halves.
Place the membrane filters on SCD Agar for bacteria and on SCA for fungi.
Similarly filter the sterile water as negative control.
Incubate the inverted SCDA plates at 30 to 35°C for 72 hrs.
Incubate the inverted SCA plates at 20 to 25°C for 120 hrs.
At the end of incubation count the number of colonies/swab.
The total number of colonies in plates exposed after disinfectant treatment should considerably very less when compared to the total number of colonies in plates exposed before the disinfectant treatment
Results: Compare the results of effective concentrations of disinfectant used for test and same concentrations will be implemented for routine cleaning of the department floors.