AOAC (EPA MB-06-09): Evaluation of Spray Disinfectant (includes standard 80 carriers)

https://www.epa.gov/pesticide-analytical-methods/antimicrobial-testing-methods-procedures-mb-06-09

Purpose and Goals

  • Evaluate and compare the antimicrobial efficacies of a novel disinfection device against a variety of microbes on different test locations in laboratory-controlled testing. 

Materials and Methods

  • This testing will be performed per the US EPA’s MB-06-09, Standard Operating Procedure for Germicidal Spray Products as Disinfectants (GSPT): Testing of Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica.
  • Glass slide carriers (approx. 25x25mm) will be inoculated with a liquid microbial suspension and dried. Microbes from each control carrier will be recovered into a solution which will be dilution-plated to provide quantifiable viable microbial burden data for each control carrier. 
  • Treated carriers will be sprayed with the disinfectant product per the manufacturer’s instructions. After the indicated contact time, the microbes from each treated carrier will be recovered into a culture tube of neutralizing nutrient solution (and a secondary sub-culture tube if necessary for complete neutralization) which will be incubated to provide qualitative growth/no growth data for each treated carrier by evaluation of turbidity in the solution. If the disinfectant product passes the performance standard, 20% of the no-growth culture tubes will be sub-cultured on nutrient agar to confirm results. 
  • This testing will include 5% organic soil (serum) in the inoculum solution. 
  • Each test will include one microbial strain:
    • Staphylococcus aureus​ ATCC 6538 bacteria,
    • Pseudomonas aeruginosa ATCC 15442 bacteria,
    • Salmonella enterica ATCC 10708 bacteria, 
    • Methicillin-resistant ​Staphylococcus aureus​ ATCC 33592 (MRSA) bacteria, 
    • Clostridioides difficile ATCC BAA-1870 or 43598 (formerly known as Clostridium difficile) bacterial spores, or
    • Feline calicivirus (FCV) strain F-9 ATCC VR-782 (a surrogate for human norovirus).
  • Each test will include 80 carriers to ensure sufficient materials for: 
    • 60 test carriers (minimum)
    • 6 unexposed control carriers (3 recovered before testing the treated carriers, and 3 recovered after testing is complete)
    • 1 viability control carrier
  • Each test will include 1 exposure time: TBD minutes. 
  • Note: Optional GLP services are available for an additional 25% fee.

Data Analysis

  • Data for the control carriers will be calculated to determine the quantifiable bacterial/fungal burden in colony-forming units per carrier (CFU/carrier) or viral burden in plaque- or foci-forming units per carrier (PFU/carrier or FFU/carrier) remaining on each test carrier.
  • Data will be analyzed to determine the consistency between replicate control carriers.
  • Treated carriers will be reported as growth / no-growth only. 

Typical Turn Around Time

  • Bacterial/fungal (per strain): 4-6 weeks following receipt of the test materials.
  • Viral (per strain): 6-8 weeks following receipt of the test materials.