Detergent drawer
The most heavily contaminated site measured in a domestic washing machine — despite being the part that holds the detergent.
Precautions
- Check the manufacturer's instructions
In detail
The detergent drawer is where the study found the highest load of anywhere it looked: the drawer chamber carried roughly 4.2 x 10^4 colony-forming units per square centimetre against a cross-site average of about 2.1 x 10^4. There is something genuinely counter-intuitive in that. The drawer holds the machine's concentrated cleaning chemistry, and it is the dirtiest measured part of it. The explanation is contact time in reverse: detergent passes through in dilute pulses for seconds per cycle, then the drawer sits damp for hours — a better description of an incubator than of a disinfected surface. Residue makes it worse rather than better, since undissolved detergent and softener form a film holding moisture against the plastic. The chamber the drawer slides into is the part nobody looks at, and it is the part the measurement singles out. As with the seal, CleaningHQ stops at where the problem is: the study quantified contamination and evaluated no treatment, so nothing here supports a claim that any product or wash temperature fixes it.
Hacks and claims involving this
- A hot empty wash cleans the machine Unresolved
- Leaving the washing machine door open Plausible mechanism, untested in this application
Sources for this page
Sources
Microorganisms (MDPI), 2021 · Scientific literature
Relied on for: That the detergent drawer chamber carried approximately 4.2 x 10^4 CFU per square centimetre against a cross-site mean of approximately 2.1 x 10^4, and that detergent drawers were concluded to be significantly contaminated with cultivable bacteria including potentially pathogenic ones. (states this directly)
Verification: a person has read the passage relied on.
Read on — The abstract and the conclusions. Supports the claim as stated.
Last reviewed by a person on .