Guide to the Standard: AATCC 100 Antimicrobial Fabric Test
The AATCC 100 test method assesses the effectiveness of antibacterial finishes on textiles by measuring their capacity to reduce or eliminate bacteria.
In this article, we will cover the AATCC 100 test methodology. You’ll learn the step-by-step procedure of the test, the significance of its results, and how to apply this knowledge to ensure your textile products meet your antimicrobial standards.
What Is AATCC 100?
The AATCC 100 test method, developed by the American Association of Textile Chemists and Colorists (AATCC), assesses the effectiveness of antibacterial finishes on textile materials. Specifically, it measures the fabric’s ability to reduce or eliminate bacterial growth. This quantitative test is crucial for ensuring that textiles treated with antimicrobial agents provide the intended protection against harmful bacteria.
How it works: The primary purpose of the AATCC 100 test is to evaluate both bacteriostatic (inhibition of bacterial growth) and bactericidal (bacterial killing) properties of textile products. By simulating conditions that encourage bacterial growth, the test determines how well the antimicrobial treatment works in real-world scenarios.
The AATCC 100 test applies to a wide range of textile products. These include:
Clothing and Apparel: Sportswear, activewear, and everyday clothing that require antimicrobial properties for odor control and hygiene.
Healthcare Textiles: Hospital linens, scrubs, and patient gowns where infection control is paramount.
Home Textiles: Bedding, towels, and upholstery that benefit from reduced microbial growth for hygiene and durability.
Public and Commercial Textiles: Hotel linens, restaurant uniforms, and public transportation seating that need to maintain high standards of cleanliness and safety.
Specialized Textiles: Baby products, military gear, and outdoor equipment that require antimicrobial properties for specific use cases.
However, it may not be suitable for:
Hydrophobic Fabrics: Fabrics that repel water might not allow proper contact between the bacteria and the treated surface, potentially leading to inaccurate test results.
Highly Textured or Porous Fabrics: These fabrics can create inconsistencies in bacterial distribution, affecting the reliability of the test outcomes.
For these types of fabrics, alternative or supplementary test methods might be required to ensure an accurate assessment of antimicrobial properties.
The AATCC 100 Test Method: The Testing Process
In the AATCC 100 test, bacteria are added to both the test fabric (with an antibacterial treatment) and control samples. After letting the bacteria incubate on both fabrics for a specified time, the remaining bacteria is measured. This provides a clear indication of how well the antimicrobial fabric killed bacteria compared to a control.
Here are the main steps involved in the AATCC 100 test method.
Sample Preparation: The process begins with preparing swatches of the antibacterial-treated test fabric alongside untreated control fabrics. These swatches will be used for subsequent inoculation and analysis.
Microbial Culture Preparation: A chosen test microorganism, commonly Staphylococcus aureus or Klebsiella pneumoniae, is cultivated in a liquid medium to ensure a consistent and active population. The concentration of the bacterial culture is then standardized to a specific level.
Inoculation: A specific volume of bacterial inoculum (1.0 ± 0.1 mL) is applied to both the treated and control fabric samples. This allows for easy enumeration of bacteria at the initial contact time (0 hours) for control samples.
Neutralization and Incubation: After inoculation, a neutralizing solution is added to half of the samples to stop the antibacterial action and maintain proper pH balance. The remaining samples are incubated at 37°C ± 2°C for 18 to 24 hours.
Mixing: Following incubation, the neutralizing solution is added to all samples. The samples are then thoroughly mixed, either by hand or using a vortex, to ensure even distribution.
Bacterial Enumeration: The neutralized solution, which contains the bacteria from the fabric samples, is diluted step-by-step to create a series of solutions with decreasing bacterial concentrations. Small amounts of these diluted solutions are then spread onto agar plates. The number of bacterial colonies that grow on the plates is counted.
Interpreting Test Results
The number of viable bacteria remaining on the treated fabric is compared to the number on the untreated control fabric. This comparison allows for determining how much the antibacterial treatment has reduced bacterial growth, indicating the efficacy of the treatment. A significant decrease in bacterial count on the treated fabric (a higher percentage reduction) indicates greater antimicrobial efficacy.
For example, if the untreated control fabric shows a bacterial count of 100,000 colony-forming units (CFU) after incubation and neutralization, and the treated fabric shows a count of 1,000 CFU, the calculation would be:
(Control CFU - Treated CFU) / Control CFU * 100% = (100,000 CFU - 1,000 CFU) / 100,000 CFU * 100% = 99% reduction
In this scenario, the treated fabric demonstrates a 99% reduction in bacterial population compared to the control. Depending on the specific application and established guidelines, this result could indicate high antimicrobial efficacy.
AATCC 100 Testing with QIMA
QIMA offers AATCC 100 and other textile testing services to ensure your textile products meet high standards of antibacterial efficacy. Our state-of-the-art laboratories and expert team provide reliable testing marked by industry-leading turnaround times for lab results.
Partner with us to enhance the quality and safety of your textiles. Learn more about our textile testing services or contact us today to book a test.
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