1.0 OBJECTIVE :
To lay down the procedure for testing disinfectant solutions.
2.0 SCOPE :
This SOP is applicable to methods for testing disinfectant solutions used in microbiology laboratory and production area.
3.0 RESPONSIBILITY :
Microbiologist : To perform the procedure as per SOP.
Head – Quality Control : To ensure the compliance of the SOP.
4.0 PROCEDURE :
4.1 Antibacterial /Antifungal Efficacy Test:
4.1.1 Use the following cultures: Escherichea coli , Candida albicans, Pseudomonas aeruginosa, Bacillus subtilis and two common isolates of environment.
4.1.2 Prepare stock solution of above mentioned cultures as per the Preparation of Culture Dilution for preparation for culture dilutions to obtain a concentration of at least 106 organisms per ml.
4.1.3 Prepare 1000 ml of the required concentration of disinfectant solution in purified water.
4.1.4 All media used shall be prepared from dehydrated media using purified water. These media should be tested for growth promotion test before use.
4.1.5 All experiments to be conducted under laminar air flow bench and media plates are to be incubated in incubators.
4.1.6 Take a sterile flask and dispense 100 ml of disinfectant solution in it. Add 1 ml of culture having106 cfu of organism to the flask. Retain the disinfectant solution inoculated with above organism for five minutes.
4.1.7 After 5 min. transfer above solution in a sterile filtration unit having 0.45 ? sterile membrane filter and filter. Rinse the membrane filter with 3X100 ml quantities of sterile 0.1% peptone water .Transfer the membrane filter on sterile soyabean casein digest agar for bacteria . For C. albicans use Sabouraud Dextrose Agar.
4.1.8 Incubate the plates of bacteria for 5 days at 30-35°C and record the observation after 5 days. Incubate the plates of C albicans Sabourauds Chloramphenicol Agar at 20-25°C for five days. Calculate the log of initial count and the final count. Subtract the log of final count from initial to get log reduction.
4.1.9 For negative control, prepare the required concentration of disinfectant with sterile 100 ml of water and filter through 0.45 ? sterile membrane filter and rinse the filter with 3X100ml quantities of sterile 0.1% peptone water. Place the membrane filter on the plate of SCDA and incubate at 30-35°C for 5 days.
4.1.10 Limits: The disinfectant solution must demonstrate 6 –log reduction in the viable count of the test organisms within 5 minutes.
4.1.11 Record the dilution data and disinfectant efficacy
Disinfectant solutions, microbiology, cleaning, purified water
