Quantitative determination of antibacterial activity of ceramic tile surfaces — Test methods — Part 1: Ceramic tile surfaces with incorporated antibacterial agents (ISO 17721-1: 2021 Standard)

Test not accredited in our laboratory.

This standard specifies a test method for evaluating the antibacterial activity of glazed and unglazed ceramic tile surfaces with incorporated antibacterial agents. To perform the test, 3 square test pieces with a side of 5 cm and a thickness of up to 10 mm (or as close to these dimensions as possible) are required. In addition, 6 control pieces, without antibacterial treatment, are included in the test. The test pieces and control pieces must be sterilized and conditioned before their surface is inoculated with the test bacteria. The test can be performed using either of the following two bacteria: Staphylococcus aureus or Escherichia coli. Immediately after inoculation, 3 control pieces are analysed to determine the bacterial recovery at time zero, and the remaining pieces (3 treated pieces and 3 untreated control pieces) are incubated at 37ºC and ≥ 75% RH for the test time indicated by the client, from among the following: 30 min, 1 hour, 4 hours, 8 hours or 24 hours. After the contact time, the number of bacteria recovered from the test and control pieces after the contact time is determined. Using this data, the antibacterial activity of the treated pieces is calculated by comparing the logarithm of the average of the counts obtained from the control and test pieces. Antibacterial activity can also be expressed in terms of percent reduction of recovered bacteria from treated test pieces after contact time compared to that of recovered bacteria from non-treated control pieces.