DTalos wrote: Thu Sep 11, 2025 6:20 pm
I did not realize that regular household bleach would cause stains on colored clothing.If bleach is still needed to disinfect clothes, do any manufacturers make non-staining bleach?
I’m a trained scientist.
TLDR. There is thus no bleach (as in hypochlorite) that won’t whiten, although lower concentration has less effect. I think I’ve accidentally spilled diluted bleach on my jeans to little detriment of the jeans. I’ve also spilled much stronger oxidants on my jeans when I did lab research; immediate bleaching, even though there was no holes.
There are also less powerful oxidants (peroxide), which can also be used as disinfectants. Note that even peroxide, at high enough concentration, will “whiten”, as is the case when using peroxide to clean a wound.
Longer version. Bleach doesn’t “stain”. Instead, what it often does is “whitens” garments dyed with a certain color. Formally, hypochlorite does this by oxidizing a double bond (often a carbon – carbon double bond, or C=C bond), including double bonds found in conjugated bond systems.
To understand color, one needs an understanding of what is responsible for coloring. At the most basic, color is merely how our eyes perceives light of a certain wavelength. What leads to different wavelength is where it gets interesting.
For instance, certain substances imparts color even though there is no colorant present. One could gather as many feathers of a blue jay as one wishes[*], but one still could not extract any blue color imparting substance that can be used as a colorant, because that blue color is due to nanostructures on the feather that refract light just a certain way. It just so happens that the refracted light has wavelength of ~450 nm, which is interpreted by our brain as blue.
This is different from the blue-ish color imparted by colorants that can be extracted. Tyrian purple, known since the times of the antiquities, is a famous example of this, with the dye responsible for the coloring obtained from secretions of a sea snail. Dyes are one type of color imparting substance, in particular, a water soluble molecule. They impart color because the responsible molecules have chemical bonds arranged in a certain way as to form a “chain” of double bonds, known as conjugated bonds (such as those C=C bonds mentioned above, usually formalized as C=C-C=C).
The alternating double and single bonds is important here. These conjugated bonds interact with white light (that is, a light having superposition of all possible visible wavelength) by being capable of absorbing certain wavelength and reflecting/refracting the rest, the reflected/refracted portion has a wavelength that predominates, and that is the color observed. One can read more about this here. Indigo is another famous dye; as shown in the formalized structure below, there are numerous alternating double and single bonds, some of which cannot be fully captured in this representation, even though the molecule is conjugated.
What hypochorite anion (or any oxidant does) is to oxidize those double bonds as to destroy the chain. Once one portion is broken, the molecule can no longer absorb a certain wavelength and ergo cannot reflect/refract the rest. Ergo, it just looks white, b/c white is what gets reflected when no wavelength is absorbed.
The reason why I used bleach on this load was to eliminate the stains caused by the dust/water mix from wiping up the water on the floor and also to disinfect what might be on those old t-shirts, because they were in contact with the floor in my home and were also mixed in the washing machine with other clothes. Do I need to use bleach to disinfect clothing or will most major brands of laundry detergent disinfect clothes?
You need to define what exactly you wish to accomplish. Deactivation of germs (virus, bacteria, or fungi), removal of dirt, removal of grease, or something else.
Hypochlorite disinfects mainly be oxidizing (see above) and denaturing. It’ll kill all sorts of germs, but the downside is already discussed above.
Detergents and quats (short for quaternary ammonium salts) are surfactants that disinfect by disrupting various surface structures protecting a microbe. Here’s a good overview of the process. Added bonus is that they are also generally good at removing dirt and oil. Don’t discount the effect of simply removing of microbes, that’s pretty much what handwashing with soap accomplishes.
[*] Generally not legal under the Migratory Bird Treaty Act, but phrased this way to illustrate a point.
