Testing of Antimicrobial Activity

• Typical Test Methods
  The antimicrobial activity of materials containing BactiBlock is typically tested using the standard norm for surface antimicrobial activity JIS Z 2801, which is equivalent to ISO 22196:2007. Depending on the specific application, other tests are also routinely carried out, such as ASTM E2149 and NCCLS. NBM has a fully equipped microbiology laboratory to carry out the tests internally or alternatively certified through external testing facilities.

Below: Typical example of antimicrobial test petri dish showing the inhibition of E.coli in a clear film.

Test Description
Main Standard used: JIS Z 2801: 2000 (revision 2006)

The data from JIS Z 2801: 2000 is usually expressed as an antimicrobial value calculated from the  difference between the Log10 number of colony forming units (CFU) on the treated surface and that measured on the untreated surface.

The population present on the untreated material after incubation should not be greater  than 2 orders of magnitude lower than that recovered prior to incubation.

The following formula is established for the calculation of the value of antimicrobial activity:

R= log (B/C)

where,

B: average of the number of viable cells of bacteria on the untreated test piece after 24 h

C: average of the number of viable cells of bacteria on the antimicrobial test piece after 24 h

The value of antimicrobial activity obtained by the testing method of this Standard shall
not be less than 2.0 for the antimicrobial efficacy of antimicrobial products.