- Standardize inoculum diluent. Results from the AATCC 100 test method are greatly influenced by the medium used to dilute the culture prior to inoculation of fabrics. Most people in the industry use saline which produces the greatest microbial reduction, but also limits assessment of growth-inhibiting effects.
- Standardize swatches. Microchem finds that when the inoculum volume is held to 1.0 ml, physical standardization of swatches enhances reproducibility. We recommend circular 5 cm diameter swatches, stacked approximately 2-4 high.
- Fully neutralize antimicrobial agents. Insufficient neutralization of antimicrobials can make fabrics appear spectacularly bactericidal when in fact they may only be bacteriostatic.
- Make sure the inoculum does not pool or puddle beneath the inoculated fabric. Liquid microenvironments physically separated from the antimicrobial agent reduce the overall microbial reductions.