Quick insights
- EN 17422 is a phase 2, step 2 quantitative surface test which is used to evaluate the bactericidal efficacy of veterinary teat disinfectants under practical conditions
- This test method is applicable for pre-milking and post-milking teat disinfectants used without any mechanical action
- Testing is done on synthetic skin surface using defined interfering substances to simulate real-world conditions
- EN 17422 uses Escherichia coli and Staphylococcus aureus as mandatory strains for testing
- Under this test, products must achieve a minimum 3-log reduction for pre-milking disinfectants and 4-log reduction for post-milking disinfectants
Summary
EN 17422 is a European standard that assesses the bactericidal activity of veterinary teat disinfectants by simulating real-world use conditions. This method is a phase 2 step 2 test and hence uses synthetic skin carriers to perform the test. Passing EN 17422 test helps manufacturers support regulatory compliance, product claims and market acceptance in many veterinary applications.
What are teat disinfectants?
Teat disinfectants are the antimicrobial disinfectants applied to the teats of dairy animals. They can be applied before or after milking and act to reduce bacterial contamination which leads to minimal risk of intramammary infections such as mastitis. These disinfectants are usually in the form of teat dips, sprays, foams, or barrier products, playing an important role in dairy hygiene programs.
Pre-milking disinfectants – They are used to reduce bacteria on the teat surface before milk collection as they minimize the possibility of microorganisms entering the teat canal during milking
Post-milking disinfectants – They are used to protect teat after milking when the teat canal remains temporarily open and more susceptible to bacterial contamination
Why does bactericidal performance matter for dairy animals?
Maintaining udder health is one of the most important practices in dairy cattle. Mastitis, one of the most significant diseases affecting dairy cattle, is caused by bacteria colonizing the teat surface and entering the mammary gland through the teat canal. Poorly performing teat disinfectants often fail to effectively inhibit bacterial contamination, causing infection spread throughout the herd.
Effective bactericidal activity is useful in:
- Minimizing bacterial colonization on teat skin
- Lower the chances of Mastitis
- Improve collected milk quality
- Support animal health and welfare
- Decrease the costs associated with antibiotic usage and other treatments
What is EN 17422?
EN 17422 is a European Phase 2 step 2 test used to determine the bactericidal activity of pre-milking and post-milking teat disinfectants applicable in veterinary settings without mechanical action. Unlike suspension tests, It uses synthetic skin as carrier and organic soil conditions to simulate real-world use conditions. This test method generates quantitative results in the form of log reduction that is used by manufacturers to support their efficacy claims. Product development and regulatory submission.
Read more – EN 17422 vs EN 1276: Which European Disinfectant Test Applies to Your Product?
Where does EN 17422 fit within Europe disinfectant framework
In European, disinfectant standards are categorised into multiple testing phases such as phase 1, phase 2 step 1 and phase 2 step 2 to validate product performance under strict test conditions before launching into the market
In the case of veterinary disinfectants, EN 17422 is the phase 2 step 2 carrier test that better represents real-world use conditions. The standard supports product validation for the European market by providing a consistent and reproducible test guidelines.
Mandatory test organisms under EN 17422
EN 17422 uses Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538P) as mandatory test organisms
How is EN 17422 test performed?
- Synthetic skin test surface is inoculated with bacterial test suspension + interfering substance and held at a specific conditions
- After conditioning time, inoculated test surface is immersed in disinfectant solution for a specific contact time
- At the end of contact time, neutralization is performed
- The bacteria are removed from the test surface using ultrasound technique
- Bacteria recovered in neutralizing solution are counted using plate count method
- The bacterial counts are compared with bacterial counts of controls
EN 17422 pass criteria for bactericidal claims
Under EN 17422 test method, the product is evaluated against control samples to understand the performance. The passing criteria for the products is:
- Post-milking disinfectants must achieve a minimum of 4 log reduction
- Pre-milking disinfectants must achieve a minimum of 3 log reduction
How does EN 17422 simulate real-world conditions
Being a phase 2 step 2 test, EN 17422 standard evaluates performance of disinfectant by simulating practical use conditions.
- It uses synthetic skin test surfaces as carriers for bacterial contact that better replicate practical teat skin in real-world
- It uses organic interfering substances to simulate residues generally seen in dairy operations
- In the test procedure, bacterial suspension is allowed to condition on the carrier before exposing to disinfectant, reflecting practical use conditions
Clean vs dirty conditions in EN 17422
EN 17422 is conducted in both clean and dirty conditions, depending on whether the disinfectant is intended for use before or after milking.
- Pre-milking disinfectant testing is performed under clean conditions using 3 g/L bovine albumin as the interfering substance
- Post milking disinfectant testing is performed under dirty conditions using 10 g/L milk powder as the interfering substance
EN 17422 vs suspension test
| Parameter | EN 17422 | EN 1656 |
| Purpose | To quantitatively evaluate teat disinfectants performance used in veterinary area | To evaluate bactericidal activity of chemical disinfectants used in veterinary area |
| Test phase | Phase 2 step 2 (Carrier test) | Phase 2 step 1 (Suspension test) |
| Scope of products | Pre-milking and post-milking disinfectants used in veterinary settings without mechanical action | Veterinary disinfectants for equipments, surface disinfection and teat disinfection |
| Interfering substance | Post-milking – Milk powder (final 10 g/L) Pre-milking – Bovine albumin (3 g/L) | For teat disinfectants
For other disinfectants
|
| Mandatory test organisms | Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538P) | General veterinary disinfectants – Enterococcus hirae, Proteus hauseri, Pseudomonas aeruginosa, Staphylococcus aureus Teat disinfectants – Escherichia coli, Staphylococcus aureus, Staphylococcus uberis |
| Log reduction | Pre-milking – ≥ 4 log reduction Post-milking – ≥ 3 log reduction | ≥ 5 log reduction |
Why does surface testing matter?
Bacteria behave differently when attached to surfaces than when suspended in liquid. On surface, they may become more resistant to disinfectants because the accessibility decreases and they interact with organic material
Teat disinfectants ate applied directly on skin and hence carrier-based test provides a more representative evaluation of the product performance as compared to suspension test. It helps manufacturers demonstrate that their formulations work effectively under conditions that closely represent real-world use cases.
Industries that benefit from EN 17422 testing
Several industries are benefitted from EN 17422 testing:
- Dairy hygiene product manufacturers
- Veterinary pharmaceuticals and animal health companies
- Dairy farms and milk producers
- Contract manufacturers
- Regulatory and quality assurance teams
How EN 17422 supports regulatory and market access goals
Testing in accordance with EN 17422 test helps manufacturers:
- Validate product formulations before commercializing them
- Providing scientifically validated data to back bactericidal marketing claims
- Generating reliable data for regulatory documentation
- Differentiate products in a competitive marketplace
- Enhance customer confidence by validating performance scientifically
Need EN 17422 testing?
At Microbe Investigations Switzerland, we offer comprehensive disinfectant testing services. Whether you are developing a new teat disinfectant, validating an existing formulation or preparing for regulatory submission, Our experienced microbiology team supports your throughout the process, from testing under EN 17422 under controlled laboratory conditions using standard protocols to generating reliable and reproducible results.
To discuss your testing requirements, contact our experts now
Read more –
EN 1656 Bactericidal Efficacy Test for Veterinary Disinfectants
FAQs
1. Which products are covered by EN 17422?
EN 17422 is applicable to pre-milking and post-milking teat disinfectants used without mechanical action.
2. What bacteria are required for testing?
EN 17422 uses Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538P) as mandatory test strains
3. Is EN 17422 a suspension test?
No, EN 17422 is a phase 2 step 2 carrier test.
4. Why is EN 17422 more realistic than suspension tests?
The standard evaluates disinfectants using synthetic skin carriers and using defined interfering substances. This better represents real-world conditions
5. Can EN 1656 results replace EN 17422 results?
No, EN 1656 and EN 17422 are used for different stages and products. EN 1656 measures bactericidal activity of general veterinary disinfectants and teat disinfectants in suspension whereas EN 17422 evaluates performance of only teat disinfectants in practical use conditions
7. What is the difference between phase 2 step 1 and phase 2 step 2 testing?
Phase 2 step 1 evaluates disinfectants in suspension under controlled laboratory conditions while phase 2 step 2 evaluates products on contaminated carriers under conditions that better simulate actual use.
8. What are clean and dirty conditions in EN 17422?
Pre-milking disinfectants are tested under clean conditions using 3 g/L bovine albumin. Post-milking disinfectants are evaluated under dirty conditions using 10 g/L milk powder, replicating milk residues and organic matter in real world conditions
9. Why do products fail EN 17422 testing?
Common reasons can be:
- Insufficient bactericidal activity on surfaces
- Reduced performance in the presence of organic matter
- Inadequate contact time
- Poor formulation characteristics affecting surface coverage
- Failure to achieve the required log reduction
10. What contact times are commonly evaluated under EN 17422?
Contact times are selected according to the product’s intended instructions for use.
12. Can teat dips and teat sprays both be tested?
Yes, they both can be tested under EN 17422
13. What log reduction is required for post-milking disinfectants?
Post-milking disinfectants must achieve a minimum of 4 log reduction to pass EN 17422 test
