How to Clean and Disinfect a Door Knob Effectively?

Did you know that Door Knob are one of the areas with the highest concentration of bacteria in homes and public places? According to a study in the Journal of Applied Microbiology, a single Door Knob surface can carry up to 3,000 pathogenic microorganisms, and its contamination level is even higher than that of a toilet seat. Especially in the peak flu season or post-epidemic era, properly cleaning and disinfecting door handles has become a key link in blocking the virus transmission chain.
1. Scientific cognition: Why do door handles need special treatment?
Cross-contamination hotspots
On average, human hands touch 300 surfaces every day. Door handles, as high-frequency contact points, are prone to accumulate pathogens such as Staphylococcus aureus, Escherichia coli, and norovirus, forming a "transit station" for cross-infection.
Material differences
The natural antibacterial properties of copper door handles can kill 99% of microorganisms in 8 hours, while common stainless steel and plastic materials do not have this property and need to rely on manual disinfection.
Material type Recommended disinfectant Prohibited ingredients Disinfection time
Stainless steel 75% ethanol Bleach 5 minutes
Brass Isopropyl alcohol Acidic solvent 3 minutes
Plastic Quaternary ammonium salt Acetone 10 minutes
Two, four-step professional disinfection process
Step 1: Pretreatment and personal protection
Wear disposable gloves (nitrile material is recommended) and use a microfiber cloth to remove visible stains on the surface. Note: Wiping with a damp cloth can reduce the risk of aerosol diffusion.
Step 2: Deep cleaning
Prepare a pH-neutral multi-purpose cleaner (such as a solution containing a surfactant) and wipe from the inside to the outside in a spiral motion to avoid missing grooves and gaps. Experiments have shown that mechanical friction can remove more than 70% of biofilms.
Step 3: Precise disinfection
Choose disinfectants according to the material:
Chlorine-containing disinfectants: 500mg/L effective chlorine (1:99 dilution of 84 disinfectant), act for 10 minutes;
Alcohol: 70-75% ethanol solution, let stand for 3 minutes after spraying;
Ultraviolet disinfection stick: suitable for medical places, 265nm wavelength irradiation for 30 seconds to kill coronavirus.
Step 4: Drying and maintenance
Wipe the surface dry with sterile paper towels to avoid residual disinfectant from corroding metal parts. It is recommended to disinfect 2-3 times a day, and it needs to be increased to once an hour in crowded places.
III. Common misunderstandings and risk avoidance
Error 1: Mixing disinfectants 84 disinfectant + toilet cleaner = highly toxic chlorine! The principle of using a single ingredient must be strictly followed.
Error 2: Over-reliance on essential oil spray Natural ingredients such as tea tree oil and lemongrass have no authoritative sterilization certification and are only suitable for auxiliary deodorization.
Error 3: Ignoring post-contact protection Even if disinfection is completed, the "20-second seven-step hand washing method" must be performed after touching the door handle.