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TEST METHOD
Quantitative Suspension Test for the Evaluation of Bactericidal Activity in the Veterinary Area
EN 1656 is an essential European Standard used to evaluate the minimum bactericidal activity for chemical disinfectants used in the veterinary area.
The infographic below provides a brief overview of the EN 1656 test method.
Understanding EN 1656 Testing
Application areas
This testing method applies to the following product applications:
- General Disinfection
- Teat Disinfection
Test Protocol
Step 1: Customer product is added to a mixture of the test suspension and interfering substance.
Step 2: After the selected contact time, 1 mL of the test mixture is transferred into a neutralizer containing distilled water to stop the disinfectant activity.
Step 3: After the required neutralization time, the neutralized mixture is plated and incubated. Surviving bacterial colonies are then enumerated to determine the log reduction.
The test protocol is performed under the specified conditions according to the product category and intended application.
Test Microorganisms
These are the obligatory test organisms for bactericidal activity. For general disinfection:
- Pseudomonas aeruginosa
- Staphylococcus aureus
- Enterococcus hirae
- Proteus hauseri
For teat disinfection:
- Escherichia coli
- Staphylococcus aureus
- Streptococcus uberis
Wish to add more microorganisms? Click here for our full list of microorganisms.
Contact Time & Concentration
The test concentration is chosen according to the manufacturer’s recommendation.
The contact time recommended by the test method differs based on product application or can be chosen based on manufacturer’s recommendation.
- The contact time recommended by the test method for general disinfection is between 1 minute to 2 hours.
- The contact time recommended by the test method for teat disinfection is between 1 minute to 30 minutes (post-milking) or between 30 seconds to 3 minutes (pre-milking).
The test temperature recommended by the test method is between 5°C to 40°C for general disinfection or 20°C to 30°C for teat disinfection.
Soiling Conditions
Interfering substances, or commonly referred to as soiling, are used to mimic organic substances found on human skin, surfaces, and instruments. These are the available soiling conditions according to the test method.
For general disinfection:
- Low level soiling: 3.0 g/L bovine serum albumin
- High level soiling: 10.0 g/L yeast extract + 10.0 g/L bovine serum albumin
For teat disinfection:
- Post-milking: 10.0 g/L milk powder
- Pre-milking: 3.0 g/L bovine serum albumin
Need help with your testing requirements?
Have questions about this test method or your product? Our technical team is here to assist you.