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TEST METHOD
Quantitative Suspension Test for the Evaluation of Yeasticidal or Fungicidal Activity in the Veterinary Area
EN 1657 is an essential European Standard used to evaluate the yeasticidal or fungicidal activity for chemical disinfectants used in the veterinary area.
The infographic below provides a brief overview of the EN 1657 test method.
Understanding EN 1657 Testing
Application areas
This test method is applicable to the following product categories:
- 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:
- Candida albicans
- Aspergillus brasiliensis (not required for teat disinfection and yeasticidal efficacy only)
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 can be chosen based on manufacturer’s recommendation depending on practicality of product application within the range:
- General disinfection: 1 to 120 minutes
- Teat disinfection: 1 to 5 minutes (post-milking) or 30 seconds to 3 minutes (pre-milking)
The test temperature recommended by the test method is between 5-40°C for general disinfection and 20-30°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 bovine serum albumin + 10.0 g/L yeast extract
For teat disinfection:
- Pre-milking: 3.0 g/L bovine serum albumin
- Post-milking: 10.0 g/L reconstituted skimmed milk
Need help with your testing requirements?
Have questions about this test method or your product? Our technical team is here to assist you.