Microbiologist dipping glass slide with dried inoculum into test product

EN 14561:2006

Quantitative carrier test for the evaluation of bactericidal activity of instrument disinfectants intended for use in the medical area.

EN 14561:2006 is a mandatory phase 2 step 2 carrier test for instrument disinfectants intended for use in the medical area.  The test evaluates the efficacy of the product against bacteria.


Test Conditions

The standard refers to the parameters to be observed when testing products intended for instrument disinfection. This includes the test microorganism, test temperature, carrier, contact time and interfering substance.

Refer to the table below for the minimum test requirement.


Test Method


In a carrier test, the test microorganism is added to the selected interfering substance and applied onto a glass slide. The glass slide represents an actual instrument or carrier of microorganism. The glass slide is then left to air-dry to simulate instrument surface or carrier of microorganism. Next, the carrier is submerged in the test disinfectant for the duration of the contact time. The carrier is then transferred into a neutralizer solution to prevent continued bactericidal activity. A sample of the neutralizer solution is then acquired, plated and incubated for 2 days. The number of test microorganism recovered is compared to the microorganism recovered from the control sample (where test microorganism is exposed to water instead of disinfectant) to determine if the test product is effective.

Diagram 1: EN 14561 test method


Log Reduction


Log reduction refers to the extent to which a product is capable of reducing the number of microbes. For example, 4-log reduction means the number of microorganisms on a surface has been reduced by 10 000 times. A product that is 99.9% effective against a certain microbe is said to have achieved 3-log reduction against that microbe.

For a product to pass EN 14561, it must be able to achieve 5-log reduction against the respective test microorganisms listed in Table 1. In other words, the product must be able to kill 99.999% bacteria while meeting all the other requirements of the European standard.

Difference between test product that pass & fail EN 14561 for E. hirae

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