CMI Infection Control & Sanitation 1 — Questions and Answers
Question 1: What is the primary difference between sanitizing and disinfecting a surface?
- Sanitizing removes dirt while disinfecting removes grease
- Sanitizing reduces microbial counts to safe levels while disinfecting kills a broader spectrum of pathogens (Correct answer)
- Sanitizing uses hot water while disinfecting uses chemical agents
- Sanitizing is used on floors while disinfecting is used on walls
Correct answer: Sanitizing reduces microbial counts to safe levels while disinfecting kills a broader spectrum of pathogens
Sanitizing reduces microbial populations to levels considered safe by public health standards, while disinfecting kills a much broader and more complete range of pathogens including bacteria, viruses, and fungi.
Question 2: What does 'dwell time' (also called contact time) mean when applying a disinfectant?
- The time it takes for a disinfectant to evaporate from a surface
- The duration the disinfectant must remain wet on a surface to achieve its labeled kill claims (Correct answer)
- The time between applying and rinsing the disinfectant
- The shelf life of the disinfectant product
Correct answer: The duration the disinfectant must remain wet on a surface to achieve its labeled kill claims
Dwell time is the period the disinfectant must remain visibly wet on the surface to kill the pathogens listed on its EPA-registered label.
Question 3: Which of the following pathogens is generally considered the MOST difficult to eliminate with standard disinfectants?
- Staphylococcus aureus
- Influenza A virus
- Clostridium difficile (C. diff) spores (Correct answer)
- Escherichia coli (E. coli)
Correct answer: Clostridium difficile (C. diff) spores
C. diff spores are highly resistant to most standard disinfectants and typically require EPA-registered sporicidal agents such as bleach-based products to be effectively eliminated.
Question 4: What is the correct order of steps for infection control cleaning of a surface?
- Disinfect, then clean, then sanitize
- Sanitize, then disinfect, then clean
- Clean (remove soil), then apply disinfectant and allow dwell time (Correct answer)
- Apply disinfectant, wipe immediately, then clean
Correct answer: Clean (remove soil), then apply disinfectant and allow dwell time
Organic matter and soil can inactivate disinfectants, so surfaces must be cleaned first to remove debris before applying a disinfectant and allowing adequate dwell time.
Question 5: Cross-contamination in cleaning operations refers to:
- Using the wrong concentration of a cleaning chemical
- Transferring pathogens from one surface or area to another via cleaning tools or cloths (Correct answer)
- Mixing two incompatible cleaning chemicals together
- Cleaning a surface that does not require disinfection
Correct answer: Transferring pathogens from one surface or area to another via cleaning tools or cloths
Cross-contamination occurs when microorganisms are inadvertently spread from a contaminated surface to a clean one through tools, cloths, or hands used without proper precautions.
Question 6: Which of the following disinfectants is most effective against norovirus on hard non-porous surfaces?
- Quaternary ammonium compounds (quats)
- Hydrogen peroxide at low concentration
- EPA-registered bleach-based disinfectants with norovirus kill claims (Correct answer)
- Isopropyl alcohol at 70%
Correct answer: EPA-registered bleach-based disinfectants with norovirus kill claims
Norovirus is a non-enveloped virus resistant to many common disinfectants; EPA-registered bleach-based products with specific norovirus kill claims on the label are most reliably effective.
Question 7: What does the EPA registration number on a disinfectant product label indicate?
- The product's manufacturing lot number for traceability
- That the EPA has evaluated and approved the product's efficacy and safety claims (Correct answer)
- The chemical concentration percentage of active ingredients
- The product's recycling and disposal code
Correct answer: That the EPA has evaluated and approved the product's efficacy and safety claims
An EPA registration number confirms that the product's claims—including which pathogens it kills and under what conditions—have been reviewed and approved by the Environmental Protection Agency.
CMI Infection Control & Sanitation 1
What is the primary difference between sanitizing and disinfecting a surface?