ASTM E2362: Standard Practice for Evaluation of Pre-saturated or Impregnated Towelettes for Hard Surface Disinfection


Purpose and Goals

  • Evaluate and compare the antimicrobial efficacies of several wipe formulas against a variety of microbes/viruses in laboratory-controlled testing. 

Materials and Methods

  • This testing will be a modification of ASTM International’s Standard Test Method E2362.
  • Test surface carriers (glass slides 25 x 75 mm) will be inoculated with a liquid microbial/viral suspension, dried, and then covered (not wiped) with a pre-loaded wipe for treatment. After the appropriate contact time, the microbes/viral particles from each carrier will be recovered into a solution which will be dilution-plated to provide quantifiable viable microbial/viral burden data for each carrier tested. 
  • This testing will include 5% organic soil (serum) in the inoculum solution. 
  • Each test will include one microbial strain:
    • Methicillin-resistant ​Staphylococcus aureus​ ATCC 33592 (MRSA) bacteria
    • Carbapenem-resistant Klebsiella pneumoniae ATCC 4352 or BAA-1705 (KPC) bacteria
    • Candida auris CDC B11903 fungus 
    • Staphylococcus epidermis ATCC 35984 bacteria
    • Salmonella enterica ATCC 10708 (formerly known as ​S. choleraesuis​) bacteria
    • Salmonella enterica​ ATCC 14028 (formerly known as ​S. typhimurium​) bacteria
    • Shigella flexneri ATCC 12022 bacteria
    • Escherichia coli ATCC 25922 (standard strain) or 43888 (a O157:H7 strain) bacteria
    • Listeria monocytogenes ATCC 7644 bacteria
    • Pseudomonas aeruginosa ATCC 9027 or 15442 bacteria
    • Clostridioides difficile ATCC BAA-1870 or 43598 (formerly known as Clostridium difficile) bacterial spores
    • Influenza A virus (H1N1) ATCC VR-1469
    • Human Coronavirus strain ​OC43​ (HCoV-OC43) ATCC VR-​1558 
    • Feline calicivirus (FCV) strain F-9 ATCC VR-782 (a surrogate for human norovirus)
    • Human rhinovirus strain 37 ATCC VR-1607
  • Each test will include 144 total data points: 
    • 4 TBD test surfaces (stainless steel, glass, PVC, etc)
    • 3 TBD wipe substrate compositions (polycellulose, polyester, etc)
    • 2 TBD wipe loads (untreated, treated)
    • 6 replicate wipes will be tested for each testing condition (2 lots x 3 wipes per lot).
  • This study’s documentation and performance will be compliant with GLP regulations.

Data Analysis

  • Data will be calculated to determine the quantifiable bacterial/fungal burden in colony-forming units per surface (CFU/surface) or viral burden in plaque- or foci-forming units per disc (PFU/surface or FFU/surface) remaining on each test surface.
  • Data will be analyzed to determine the consistency between replicates.
  • Data will be analyzed to compare the efficacies of each test condition to determine the percent reductions and log reductions of microbial burdens compared to controls. 

Typical Turn Around Time

  • Bacterial/fungal (per strain): 6-8 weeks following receipt of the test materials.
  • Viral (per strain): 8-10 weeks following receipt of the test materials.