Cleaning Validation and Disinfectant Efficacy

By on 15 April 2020

Disclaimer: The guidelines set out in this document is the opinion of SMT LABS.


According to Good Manufacturing Practice (GMP) regulations, guidance from the Food and Drug Administration (FDA) and manufacturers of bio-pharmaceuticals, facilities must demonstrate that harmful residue or organisms are properly removed during cleaning to ensure the correctsafety levels are met, thereby eliminating contamination of manufacturing equipment. Food preparation surfaces and equipment that come into contact with food may be contaminated with several different types of microorganism. An effective disinfectant is required to kill a wide range of bacteria on a surface, not just those known to be responsible for food poisoning.

Microbial contamination control is essential in ensuring consumer safety, especially in controlled environments. Disinfectants play an important role in controlling microbial contamination on surfaces. The term disinfectant is often broadly used to describe chemical agents used to reduce the microbial load of controlled environments. Equally important is the use of an effective hand sanitizer in order to ensure that the hands of food handlers are clean.

There are many disinfectant (also often referred to as sanitisers) manufacturers claiming that their product will kill 99.9% of all bacteria. Although this sounds extremely efficient, it does not prove that a product is an effective disinfectant and that it is indeed able of killing a wide range of bacteria. In order to demonstrate effectiveness, disinfectants should be tested using European Standard Test Methods for their efficacy.

Disinfectant efficacy testing is utilized to measure the effectiveness of chemicals that are used to clean, sanitize, or disinfect surfaces (including hand sanitizers). There are many regulations and guidance documents that focus on disinfectant efficacy testing. Establishing a compliant disinfectant efficacy testing package aids in providing clear documentation that the disinfectants employed in a facility have been analysed as required by these regulations.

Cleaning validations are conducted to show that the cleaning process and frequency, including any mechanical cleaning actions, are sufficient to maintain surfaces in a defined state free of product, cleaning chemical residue and adventitious infectious organisms. These studies demonstrate that equipment and food contact surfaces can be cleaned in such a manner as to achieve the desired/accepted chemical and microbiological load.

Disinfectant efficacy studies or disinfectant validation studies are performed to demonstrate that disinfectants used on surfaces in manufacturing areas, laboratories and other facility areas are effective in inactivation or removal of microorganisms, such as bacteria, yeast and mould. Disinfectant studies can support cleaning studies by indicating that application of the disinfectant reduces or eliminates microorganisms, however these studies should not be considered a substitute for establishing that the cleaning agents and physical cleaning actions are acceptable. Proving that a disinfectant is effective is a necessary part of ensuring cleanliness, however there should also be ensured that it is used in the correct manner in the facility.

Cleaning Validations

There are various steps that should be considered during Microbiological Cleaning Validation, some of which are listed below:

  • Protocol and Sampling Plan – establish the site to be sampled for microorganism contamination, the collection method to be used and how data will be handled.
  • Risk Identification – define the health-based exposure limits as suggested by the guideline of the facility or governing body such as the FDA.
  • Method Qualification/Neutralization/Recovery Execution – establish that microorganisms can be recovered in an acceptable range from the surface using the proposed collection method. Neutralization studies of cleaning agents or disinfectant residues are incorporated into this phase of the study if needed.
  • Sampling Plan Execution and Analysis – collection of samples is performed using the determined method and samples are evaluated for microorganisms prior to and/or after the cleaning procedure is performed to show that cleaning was effective.
  • Routine Monitoring – periodical analyses of collected samples after cleaning to ensure that the process remains effective over time.

Disinfectant Efficacy Studies

A disinfectant study confirms that disinfectant agents used are active against organisms isolated during the environmental monitoring program of a facility and/or against other relevant organisms which can be used as a model to determine efficacy under experimental conditions. The experimental conditions should simulate the practical use of the disinfectant where necessary. These studies, which are especially critical for sterile manufacturing facilities, have been performed for bacteria, yeast and mould for many years. Phases for Disinfectant Studies

  • Study Design and Protocol Generation – determine microorganisms, surfaces, disinfectant and treatment conditions to be tested.
  • Surface Efficacy Studies – determine the effectiveness of inactivation of the desiccated microorganism by disinfectants on appropriate surfaces.

Disinfectant Efficacy Testing Regulations and Concepts



Chemical disinfectants and antiseptics – Quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics used in food, industrial, domestic and institutional areas.


This European Standard specifies the testing procedure and minimum requirements for bactericidal activity of chemical disinfectant and antiseptic products that form a homogeneous, physically stable preparation.

Obligatory test organisms:

Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus hirae

Additional test organisms:

A variety of additional test organisms can be used, depending on availability from testing laboratories.

Test conditions – interfering substances:

The interfering substance used can be applied at a concentration that simulates clean and dirty conditions respectively. This is industry and application specific.


Log reduction of > 5 for bactericidal activity (> 4 log reduction for hand rubs and > 3 log reduction for hand wash).



Chemical disinfectants and antiseptics – Quantitative non-porous surface test for the evaluation of bactericidal and/or fungicidal activity of chemical disinfectants used in food, industrial, domestic and in institutional areas.


The test should be performed at a temperature between 18°C and 25°C and a recommended contact time of 5 minutes for bactericidal activity and 15 minutes for fungicidal activity. The test can be performed under clean and/or dirty conditions. The product should be tested at three concentrations (minimum), including one in the non-active interval and another in the active interval. The product is tested on stainless steel discs and bactericidal or fungicidal activity evaluated by the method of dilution-neutralization. To consider the product bactericidal, it must demonstrate a log reduction of greater than 4 in the number of viable bacteria and to consider the product fungicidal it must demonstrate a 3-log reduction in the number of viable cells or fungal conidia. Obligatory test organisms: Bacteria: Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus hirae. Fungi: Aspergillus brasilliensis, Candida albicans. Additional test organisms: A variety of additional test organisms can be used, depending on availability from testing laboratories. Test conditions: The interfering substance used can be applied at a concentration that simulates clean and dirty conditions respectively. This is industry and application specific.


Log reduction of > 4 for bactericidal activity and > 3 for fungicidal activity.

Why Choose SMT LABS for cleaning validation and Disinfectant Efficacy Studies?

  • SMT LABS is one of the very select few laboratories in South Africa that is SANAS accredited for both EN1276 and EN13697 methods.
  • We offer an excellent turn-around time of 10 working days per chemical efficacy test.
  • Affordable testing.
  • Guidance by knowledgeable staff members regarding your chemical efficacy testing results.
  • Personal attention to your specific enquiries.
  • Courier for the collection of your samples at your doorstep.


As people become more and more aware of quality and the dangers involved with consuming contaminated food, the focus on providing quality goods has increased exponentially. Given the current economic situation the concept of “only the strongest will survive” has come into play. Companies that fail to deliver a quality product will eventually be out-competed by companies that win consumers over by providing quality products. When looking beyond the financial implications, at the actual reason behind quality, are the consumers. The people whose lives we strive to protect by the practises we adhere to in our facilities, be it manufacturing, produce or laboratories. Hygiene, cleanliness and good quality has become and will continue to be the buzz word when consumers discuss which goods to purchase. Regular testing of the cleanliness of your facility will ensure that you protect consumers as well as avoiding financial and reputational damage due to recalls and contaminated products. Test today, improve tomorrow!


  1. Cleaning Validation and Disinfectant Efficacy Studies,
  2. 5 Key Components of a Compliant Disinfectant Efficacy Testing Package (Part 1),
  3. CEN – EN 1276,
  4. Microbiological Testing Summary,
  5. Does your product pass EN 1276,
  6. Valencian Institute of Microbiology,

For more information, please contact:

Tel: 073 169 4343