Summary of the AATCC 100 Test Method, Modified for Viruses
The stock virus is thawed and diluted to the titer requested by the Study Sponsor.
If requested, the viral inoculum is loaded with organic soil to the appropriate level (generally 5% animal serum).
Test and control textiles are cut to swatches of the appropriate size for the study.
A 1.0 ml inoculum volume is applied to the test and control swatches, taking care to ensure that the suspension touches only the textile. The inoculum must be fully absorbed- more swatches can be added if necessary.
A 1.0 ml inoculum volume is also applied to a separate set of untreated cotton swatches to serve as the "Time Zero" control
The "Time Zero" control is immediately neutralized in the appropriate media. The suspension is serially diluted and each dilution is plated in quadruplicate to host cell monolayers.
The test and control swatches are allowed to incubate at the selected temperature for the duration of the contact time.
At the close of the contact time, the test and control swatches are neutralized. The harvest suspensions are serially diluted and each dilution is plated in quadruplicate to host cell monolayers.
The enumeration assay is allowed to incubate at the appropriate temperature for the test virus, usually for 7 days.
The enumeration assay is scored using standard cell culture techniques.
Strengths of the AATCC 100 Test Method, Modified for Viruses
The method states the inoculum must be fully absorbed by the textile. This helps to facilitate maximum contact between the virus and the active contained in or on the textile.
Viral survivability is generally higher on fabrics than on hard, nonporous surfaces. This can allow for longer contact times to be tested relative to hard surface methods since the test virus will not be inactivated as quickly on the control textile.
Weaknesses of the AATCC 100 Test Methods, Modified for Viruses
The method does not state success criteria. Success is ultimately determined by the Study Sponsor.
Care is taken to ensure that the inoculum does not dry out over the course of the contact time. This does not necessarily reflect the conditions encountered in real use of the fabric.