Disinfectant Testing
In the pharmaceutical and associated industries, the subject of disinfectant validation is attracting ever-increasing attention from regulatory bodies such as MHRA, IMB and FDA. Companies are expected to be able to demonstrate conclusively that their disinfectants of choice are effective under the conditions in which they are used.
A recognised approach to disinfectant validation is to follow the CEN (European Committee for Normalisation) Technical committee 216 work programs which provide a systematic approach to the validation of disinfectant efficacy.
A number of EN methods have been issued as a result of the CEN work program. The literature defines in detail how distinfectants should be tested against a range of type cultures under controlled conditions. There are clearly defined pass criteria and results are expressed as either pass or fail. All the methods include rigorous validation requirements which are performed in parallel to the test itself.
Test In-house or Outsource?
There are two compelling reasons for outsourcing disinfectant validation:
- Disinfectant testing has a long, steep learning curve and can be extremely time consuming for those not fully familiar with the methods.
- For most companies, the testing is either one-off or occassional. This together with the investigative nature of the work means there is no understanding of what results may be expected. Because MGS performs disinfectant testing for many customers, we have a database of results which we use to check for out-of-trend results and offer advice should disinfectant peformance be disappointing.
EN Methods
The CEN approach has three phases:
Phase |
Step |
Description |
Industrial |
Medical |
Veterinary |
|---|---|---|---|---|---|
1 |
Basic bactericidal and fungicidal activity |
EN 1040 |
|||
2 |
1 |
Quantitative suspension testing to evaluate bactericidal, fungicidal and sporicidal activity. |
EN 1276 |
EN 13727 |
EN 1656 |
2 |
2 |
Surface testing |
EN 13697 |
EN 14561 |
EN 14349 |
3 |
Field trials - yet to be developed |
At MGS we are familiar with all these and many other disinfectant test methods.
However it is the wider application of the standard EN methods that is the key to thorough, coherent disinfectant validation program.
Wider Application of the EN Methods
The EN methods themselves are of value as a means of determining the efficacy of a disinfectant under controlled conditions. However, in normal working conditions, environmental organisms are encountered which can provide a much more stringent challenge to disinfectant products.
The nature of the EN methods is such that they can be adapted to form the basis of more informative studies into the performance of disinectants in practice. This can yield valuable information about the comparative performances of a number of products and also facilitate studies of the effects of changes in product concentration, contact time, test temperature and the use of water produced in your facility, all of which help to evaluate your specific in-house cleaning procedures.
Handwashes and Handrubs
pR EN 12054 (withdrawn) evaluates the basic bactericidal activity of products for hygienic and surgical handwash and handrub.
EN 1499 and EN 1500 are specifically designed to test handwashes and handrubs. Both methods involve the use of a panel of volunteers who use the product under test and a reference material.
EN 12791 evaluates the action of surgical hand disinfectants, including sustained action.
Mycobacterium
EN 14348:2005 is a quantitative suspension test for the evaluation of mycobactericidal activity of chemical disinfectants for instruments used in the medical area - Test method and requirements (Phase 2, Step 1).
Viricidal Testing
MGS is able to coordinate testing of disinfectants against a number of viruses included Influenza A, Herpes and FIV (Feline Immunodeficiency Virus) - an accepted surrogate of HIV.
Alternative Disinfectant Test Methods
For companies not wishing to follow the CEN approach, a number of alternative methods are available for the evaluation of disinfectant products, including but not limited to the following:
6471:1984 (withdrawn) Determination of the antimicrobial value of QAC disinfectant formulations.
EN 6424:1990 (withdrawn) QAC based aromatic disinfectant fluids.
EN 541:1985 (withdrawn) Determination of the Rideal Walker coefficient of disinfectants.
Kelsey Sykes Test 1974 is used to estimate concentrations of disinfectants which may be recommended for use under “clean” and “dirty” conditions.
AOAC 991.47:1991 Hard surface carrier test method.
AOAC 960.09:1980 Germicidal and detergent sanitising action of disinfectants.
AOAC 955.11:1964 Phenol Coefficient Method.
