AATCC 100-Evaluation of antimicrobial in tissue. AATCC 100: 2012. A ssesment of antimicrobial finishes on textile materials.  

Test accredited by ENAC (National Accreditation Entity). 

Antimicrobials are useful as additives in fabrics for several reasons: 1) because they provide protection against odors caused by the presence of microorganisms without altering the appearance or feel of the product, and 2) because when the fabrics are used in the health area can help prevent infections in patients. For these reasons, fabrics with antimicrobial activity are demanded for sports and commercial garments, and in the medical area. In the medical area can prevent infections by contaminating microorganisms of public interest , such as methicillin-resistant Staphylococcus aureus (MRSA), among others. Both when the antimicrobial is incorporated into the fibers, as if applied to the fabric surface, it is necessary to test their effectiveness. The AATCC 100 method is considered the standard method in the textile industry to measure the antimicrobial activity of an antimicrobial material, as reveal whether fabrics or tissues inhibit the growth or kill bacteria when exposed to them over a period of 24 hour contact. This method is performed with bacteria grown in liquid medium at a standardized concentration, which are inoculated into fabrics at suitable dilution, so as to contact them, determining the concentration of the bacteria both in zero time. You can also perform the test at another time of contact, for example. 1 hour to 6 hours. After exposure, the bacteria are eluted in a neutralizing solution and allow  the growth of viable bacteria if present. The method is performed in parallel with pieces of fabrics control without antimicrobial allowing comparatively demonstrate the effect obtained with the fabric containing the antimicrobial, and thus determine the concentration of bacteria and their reduction, if it exists. For showing, reduction in the number of bacteria after the period of contact with respect to the initial concentrations to be calculated both fabrics with antimicrobial, and the respective controls without antimicrobials. This method is quantitative and reproducible, and can determine both bacteriostatic antimicrobial activity, inhibiting the growth of bacteria, bactericidal and antimicrobial activity, which kills bacteria. This method is performed in the presence of nutrients and growth conditions suitable for multiplication of bacteria used, so that inhibition of growth or death only occurs if the fabrics are sufficiently antimicrobial. To perform the method properly fabrics must absorb liquids, i.e. they should not be hydrophobic. The test is performed with circular pieces of fabric of 4.8 cm in diameter, with antimicrobial and without antimicrobial (controls) with or without sterilization, with or without prior washing, as recommended by the manufacturer, using two species of bacteria (Klebsiella pneumoniae and Staphylococcus aureus). The contact between bacteria and the fabrics to incubate a "zero" time or a time chosen by the customer and then bacteria are eluted with a neutralizing solution for quantifying, calculating the reduction rate. As further optional microorganisms methicillin resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Enterococcus resistant to vancomycin, Salmonella spp be used. or any other chosen by the customer. To perform the test the customer must provide fabric pieces 4.8 cm in diameter, both antimicrobials as without antimicrobial in sufficient numbers to perform the process in duplicate with both species of bacteria ( at least 32 pieces with antimicrobial and 16 pieces with no antimicrobial).