SOP on Testing Efficacy of Disinfectants

SOP on Testing Efficacy of Disinfectants.

Objective: To lay down a procedure for testing efficacy of Disinfectants.

Scope : This SOP is applicable for testing of efficacy of disinfectant solutions used in  microbiology laboratory and production area.





Head-Quality Control

Head-Quality Assurance


Prepare Culture suspension of Escherichia coli ATCC 8739, Candida albicans ATCC 10231 Pseudomonas aeruginosa ATCC 9027, Bacillus subtilis ATCC 6633 and a common isolate of environment as per SOP.

Prepare stock solution of the above culture suspensions to obtain a concentration of at least 1000 organisms per ml.

Prepare 1000 ml of the required concentration of disinfectant solution in sterile water for injection or purified water as per SOP.

All activities shall be carried out under Laminar Airflow bench.

Dispense 100 ml of disinfectant solution prepared into a sterile container.

Inoculate it with 1 ml from dilution containing 1000 CFU/ml (or 0.1 ml of 100 CFU).

Give a contact time as per the table for different disinfectants.

After the elapse of Contact time, filter the disinfectant solution through a filtration unit having 0.45 m sterile membrane filters.

Rinse the membrane with 3 x 100 ml of Sterile 0.1% Peptone water.

Transfer the membrane onto Soyabean casein Digest Agar for Bacteria and Sabouraud Dextrose Agar for Candida albicans.

Incubate the plates for 5 days at 30-35 0C for Bacteria and 20-25 0C for Candida albicans.

Calculate the log of initial count and the final count. Subtract the log of final count from initial to get log reduction.

Record the details.

Run a negative control by filtering the disinfectant solution only followed by rinsing with 3 x 100 ml of 0.1% Peptone water and placing the membrane onto respective agar plates.

                  Table for Disinfectants, Contact Time and Effective Concentration.

Sr.No            SNo Disinfectant Contact Time

(in min)

Effective Concentration (%)
1 Sterillium 5 undiluted
2 IPA 10 70
3 Savlon 10 2.5
4 Combatan DS 5 1
5 Protasan DS 10 1
6 Triple 100 10 1
7 Lyzol 10 1
8 Domex 10 1

Frequency: Every new lot shall be tested for disinfectant efficacy.

List of Annexure:

Disinfectant  Efficacy Test Report – Annexure – I.

Reason for revision

Not Applicable due to first version


SOP : Standard Operating Procedure

No : Number

IPA :Isopropyl Alcohol

CFU : Colony forming Unit.

Annexure – I

Disinfectant Efficacy Test Report

Serial dilution of micro- organism

A.R No:

Date of test      :                                                   Date of observation:

Media lot No       :                                                   Date of prep. :


Name of organism Serial dilution using 0.9% saline solution.
1:100 1:1000 1:10000 1:100000 1:1000000 1:10000000

Incubation temperature:

For Bacteria:  30 to 35°C                                                    For Fungus   : 20 to 25° C


Name of disinfectant:                                                   Media Lot No           :

Concentration          :                                                   Date of prep.           :

Date of test                 :                                                   Date of observation:

Observation table:

Sr.No Name of organism Initial count Log of Initial Count Count observed after contact time in cfu/ml Log of Final Count Log Reduction=Log(Final count)-Log(initial Count)
Negative Control Positive Control `

Remarks: The bactericidal/fungicidal activity is achieved within…………min at concentration   of ______________________________________.

Done by:                                                                                         Checked by:

Date:                                                                                                 Date:

About Pharmaceutical Guidanace

Ms. Abha Maurya is the Author and founder of pharmaceutical guidance, he is a pharmaceutical Professional from India having more than 18 years of rich experience in pharmaceutical field. During his career, he work in quality assurance department with multinational company’s i.e Zydus Cadila Ltd, Unichem Laboratories Ltd, Indoco remedies Ltd, Panacea Biotec Ltd, Nectar life Science Ltd. During his experience, he face may regulatory Audit i.e. USFDA, MHRA, ANVISA, MCC, TGA, EU –GMP, WHO –Geneva, ISO 9001-2008 and many ROW Regularities Audit i.e.Uganda,Kenya, Tanzania, Zimbabwe. He is currently leading a regulatory pharmaceutical company as a head Quality. You can join him by Email, Facebook, Google+, Twitter and YouTube

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