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ISO 17721

Evaluation of the Antibacterial Activity of Ceramic Tile Surfaces

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ISO 17721 : 2021 – Quantitative Test Method for antibacterial activity of ceramic tile surfaces

ISO 17721 is a quantitative test method to evaluate the antibacterial activity of ceramic tile surfaces. ISO 17721 test can be used for both glazed and unglazed ceramic tile surfaces that are impregnated with antibacterial agents.

ISO 17721 Test Conditions & Requirement

Sample preparation – 3 treated test samples and 6 untreated control samples ( without any antibacterial activity) of size approximately (50 ± 2) mm × (50 ± 2) mm square or as close to this size are used for testing.

Preconditioning – Both test and control samples are sterilized before the preconditioning step.
Conditioning beds are made by placing a grade #1 Whatman filter paper of size 150 mm or equivalent onto a sterilized petri plate. Filter paper is wet thoroughly with sterile deionized water, and then test and control samples are placed individually on wet filter paper. These petri plates are further placed in an incubator maintained at 37 ± 2 °C and ≥75 % relative humidity for 18 h – 24 h. During the incubation period, it’s important to ensure that the filter paper remains wet.

Test Process of ISO 17721

ISO 17721 Test Method

  • Both the control and test sample are inoculated with the bacterial suspension. A sterilized polyethylene film is then placed on top of the inoculum to ensure a uniform spread of the bacterial suspension across the surface, while preventing any leakage from edges.
  • For 0 hr recovery of bacteria, 3 control samples inoculated with bacterial suspension are immediately transferred to SCDLP broth or other suitable neutralizer. Solution is shaken vigorously To ensure a good recovery of the bacteria from the control surface .
  • 3 treated and 3 non-treated samples are incubated at 37 °C ± 1 °C and ≥75 % RH for the desired contact time period. The recommended contact times are 30 min, 1 hr, 4hr, 8hr, and 24 hr, respectively.
  • After the incubation period, both treated and untreated test specimens are transferred to neutralizing solution and shaken to remove bacteria from film and test surfaces.
  • Washout solution with the recovered bacteria is serially diluted in PBS, and then plated and incubated at 37 °C for 24 h – 48 h to determine the remaining viable microbial count.

Note – Other enumeration techniques such as luminescence can also be used to determine the bacterial viable count.

Importance of ISO 17721 Test

Inanimate surfaces such as floor tiles serve as a great reservoir of pathogenic bacterial strains. This is due to the ability of bacterial strains to colonize the non – living surfaces and survive for extended periods of time. Consequently, the chances of microbial contamination and infections increase in various settings like homes, restaurants, and similar environments.

Antibacterial ceramic tiles have been developed to mitigate the risk of infection transmission from solid surfaces. These tiles incorporate antibacterial agents into their surfaces, effectively eradicating bacteria upon contact.

ISO 17721 establishes a quantitative testing methodology wherein antibacterial ceramic tile surfaces are challenged with specific microorganisms of concern.

Looking for ISO 17721 testing services for ceramic tile surfaces! For additional details such as  price quote, estimated turnaround times, or to schedule a consultation, please feel free to reach out to MIS experts.

At MIS,  we offer a comprehensive range of antibacterial testing services, catering to diverse product developmental needs across different sectors.  By employing cutting – edge technologies, we consistently uphold the highest standards in all services that we offer to our esteemed clients. 

To  get a quote on ISO 17721 or want to know more about our testing facilities, contact our experts here.


ISO 17721 test describes a quantitative test method for ceramic tile surfaces that have been treated with antibacterial agents. This method determines the potential of a test specimen against microbes, thus ensuring its suitability for intended applications.

ISO 17721 test is applicable for ceramic tile surfaces impregnated with antibacterial agents.

ISO 17721 test takes 3-4 weeks to complete.

At MIS, we test for ISO 17721 using the following microbial strains: Escherichia coli (ATCC 8739 and Staphylococcus aureus (ATCC 6538P).

Contact us for more information

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