Plastic Free Laundry

Ahh, laundry day. The eternal chore.

I bet you were hoping this would be a quick list of the best options for plastic free laundry detergent solutions. Yeah, me too. That’s what I set out to write, but the more I researched, the more I realized it wasn’t going to be that easy.

It turns out that there’s more to laundry than I ever cared to wonder, especially when it comes to thinking about how often we even need to wash our clothes, and the best ways to get them actually clean and hygienic, not just clean-looking and dirt free.

But, I appreciate my readers, and in case any of you are willing to take my advice, no questions asked, I’ve decided to put the recommendations first and explanations later.

Aug. 2020 Update: This post was originally published in July 2019. For updated product information and recommendations, check out the Plastic Free Laundry Detergent Comparison Guide.

If you want to know why I’ve included the detergents I have and not included others that have “eco friendly,” “plastic free,” and zero waste claims, or learn the answers to important questions like, “How often do I need to wash my clothes, anyway?“, “How “clean” do washing machines even get our clothes?“, and “Does the sun kill germs and help clean clothes?” make sure to read on after the laundry detergent recommendations!

Plastic Free Laundry Detergent – Top Recommendation

Dropps

My #1 recommendation for plastic free laundry that will actually effectively and hygienically clean your clothes is Dropps.

It’s a flexible subscription-based service delivering laundry pods (and other products) in plastic-free, cardboard boxes.

Because I have a small household, just me and my husband, I’ve been ordering their Fragrance Free Household Bundle, which includes 32 laundry detergent pods and 32 dishwasher detergent pods. Right now, with the subscription discount, it’s costing me $20, which works out to about $0.32/load. I’ve been happy with the cleaning ability of both products.

However, given what I have most recently learned in my research for this article, I intend to switch my order to their Fragrance Free Laundry Bundle, which includes 32 laundry detergent pods and 32 “Oxi Booster Pods”. At current prices it works out to about $0.64/load.

June 2020 Update: It appears that they no longer offer the products as “bundles,” so I will be ordering them separately next time I need to reorder. I’ve been very satisfied with the detergent and booster pods and they continue to be my #1 recommendation!!

Importantly, their Laundry Oxi Booster Pods not only contain a chlorine-free bleach (in the form of sodium percarbonate), but also the critically important bleach activator TAED. For information on why these two ingredients are so important when it comes to washing laundry, skip to How “clean” do washing machines even get our clothes, anyway?

Other Options – Reduced Plastic Laundry Detergents

I’m recommending these laundry detergent options with reservations.

Powdered Laundry Detergents with Color Safe Activated Oxygen Bleach AND Bleach Activators (aka Tide)

I would like to emphasize that I am not a chemist, just a layperson trying her best to understand some chemistry that I think it pretty technical and fairly over my head.

The bleach activator NOBS (nonanoyloxybenzenesulfonate) was originally created by Procter & Gamble, the company that owns Tide and Gain, among many other brands. I expected to see it listed as an ingredient in their laundry detergent powders, but I didn’t see that exact phrasing. Instead, it lists “Sodium Phenylnonanoate Sulfonate”. Tide Original Powder on Instacart and CVS both describe the ingredient “Sodium Phenylnonanoate Sulfonate” as the bleach activator.

On the P&G ingredients website, it describes that ingredient as “Wash Aid / Whitens And Brightens Clothes.” Which is distinct from other ingredients which are described differently, like “surfactants” and “process aids.” (They also list “Sodium Carbonate Peroxide” as an ingredient, described as “Color Safe Bleach / Whitens And Brightens Clothes,” also called sodium percarbonate.)

I couldn’t find much information on it elsewhere online, but given the descriptions and the similarity of the names (nonanoyloxybenzenesulfonate vs. sodium phenylnonanoate sulfonate) my best guess is that they are the same chemical, or close enough to the same chemical, and that it is indeed a bleach activator. I don’t know why they couldn’t just say that on their website – would have saved me hours of research!

Okay, so now that we’ve pretty confidently established that Tide Original Powder contains both a color safe bleach and a bleach activator, the two most important ingredients for hygienic and sustainable laundry, why am I not wholeheartedly recommending these products? There’s a few reasons:

1. I don’t use them personally. It feels weird to give them a stronger endorsement when I don’t use the product myself. I can’t say with confidence, “Yes, this product does get my clothes really clean” because I haven’t tried it. Maybe that’s a lame excuse and I should be out there testing different brands, but this is where we are right now.
2. I’m not sure their containers are totally plastic free. This is related to not using the product myself. I semi-remember using them in the laundromat as a kid, and I think there was some sort of plastic strap involved somewhere. That may have changed, but I am not sure. Maybe I should be more adventurous and check for myself, but when I already have a solution I like, I don’t want to go out and buy something else with the risk of buying a product with plastic. If anyone reading uses the product and knows how much plastic is involved, please share in the comments!
3. I hesitate to recommend P&G brands because the company doesn’t have an overall good track record for environmental protection. For example, the NRDC gave Charmin Ultra (a P&G brand) an F rating on their Toilet Paper Sustainability Scorecard, and in their report “The Issue with Tissue” they write, “Furthermore, all its at-home tissue products—Charmin, Bounty, and Puffs—continue to rely entirely on virgin forest fiber, and the company has made little progress on increasing its use of alternative fibers or recycled content in its at-home brands.” Personally, given a choice between a company with a so-so environmental track record and one that puts the environment and being plastic free at the forefront, I’m going to choose the second one.

That said, there’s no perfect solution for sustainability that works for everyone, and we all have to make trade-offs. Another argument in favor of these products is cost.

An affordable pre-made laundry detergent powder with the two important ingredients, sodium percarbonate + bleach activator (NOBS or TAED), is still a better environmental choice than a plastic jug of heavy liquid detergent.

Maybe paying $0.64/per load of laundry with detergent + activator from Dropps just isn’t in your budget, and what’s economically sustainable for you is 102 loads of Tide Original for $19 at WalMart. That’s about 19 cents a load, which means for the same price you’re getting almost 3 times as many loads.

Maybe you like the idea of DIY but you don’t want risk damaging your machine, or you just don’t have the time and/or energy to spend on tracking down plastic free ingredients and experimenting with recipes and ratios. In that case, an affordable pre-made laundry detergent powder with the two important ingredients, sodium percarbonate + bleach activator (NOBS or TAED), is still a better environmental choice than a plastic jug of heavy liquid detergent.

Powdered Laundry Detergents with Color Safe Activated Oxygen Bleach but WITHOUT Bleach Activators

Given the information I found during my research on the importance of bleach activators for getting laundry actually clean I hesitate to recommend any brand of laundry detergent that doesn’t contain both an activated oxygen bleach (AOB) AND a bleach activator (i.e. NOBS, TAED).

The short explanation is that studies show that without a bleach activator, activated oxygen bleaches like sodium percarbonate aren’t as effective. Of all the options, they just aren’t the safest bet as far as antimicrobial, hygienic washing is concerned.

That said, not all laundry needs to be washed to the same antimicrobial standards. For more details on this, skip to How often do I need to wash my clothes, anyway? and Efficient Laundry Practices.

For laundry that doesn’t need to be washed with high antimicrobial standards in mind, a plastic-free powdered laundry detergent without an activator is a perfectly acceptable choice.

The following brands DID list an AOB in their ingredients, but did NOT list an activator:

• Biokleen Free and Clear Laundry Powder
• Seventh Generation Powdered Laundry Detergent [***Sept. 2020 Update – Seventh Generation appears to no longer carry this product***]
• Nellie’s Oxygen Brightener (a laundry booster, not a detergent)
• Arm & Hammer Powder Laundry Detergent, Perfume and Dye Free and Arm & Hammer Powder Laundry Detergent plus OxiClean

This list is not comprehensive. I’m only including brands I came across while looking specifically for plastic free laundry detergent options.

As with my hesitations against recommending powdered laundry detergents with activators, I hesitate to recommend these products when I haven’t used them personally. I can’t say from personal experience how well they work OR whether they are completely plastic free. I also cannot attest to how “plastic free” these options are either. For example, Nellie’s products come in a variety of containers, some in metal, others in plastic pouches. The others may have hidden plastic not shown in pictures online.

One advantage of commercially available products over the DIY versions is that they tend to have been tested more to see that they work and do not damage machines; they also come with dosing instructions and don’t require any guesswork. That appeals to me.

No Bleaching Agent or Activator

These options pitched themselves as being environmentally friendly, but their ingredients lists did NOT include a bleaching agent or activator, at least as far as my non-chemist trained eyes could see. For more on why bleaching agents are so important, jump to “How “clean” do washing machines even get our clothes?” below.

• Tru Earth Laundry Eco-Strips (also called Dizolve Eco-strips)
• EC30 Laundry Detergent swatches (also note that EC30 is a brand of Procter & Gamble aka P&G, the same company that owns Tide, Gain, Downy, Charmin, etc.! See WSJ article “Forget Tide Pods. P&G Bets Water-Free Soap ‘Swatches’ Are the Future.” from April 22, 2019. Sorry if it’s behind a paywall. As I mentioned in the section on Tide, I just have a hard time endorsing P&G when they don’t have a very good environmental track record.)
• Sheets Laundry Club

Again, this list is not comprehensive; I have only included brands I found when searching specifically for plastic free or reduced plastic options. It seems like more options are coming out all the time as more people are interested in being more environmentally conscious and as the plastic free movement gains momentum.

If you come across a brand not listed here and would like to know more, please leave a comment and I will do my best to analyze it and give you my assessment.

June 2020 Update: I have moved this category from the “Not Recommended” section to the “Other Options” section. I hesitate to move them to the “Top Recommendation” section for a few reasons.

I haven’t tried these myself, therefore I cannot attest to 1) how well they work, and 2) how “plastic free” the products really are. For example, TruEarth did recently adapt their packaging to be plastic free, but I don’t know their shipping methods, and I’d be disappointed if it arrived in a plastic sleeve.

But upon further consideration, I thought they deserved to be in the “Other Options” section because they do have one advantage over the Dropps laundry detergent pods (which also do not have the AOB or activator – that’s only found in the Oxi Booster Pods). These options do not contain water, making them much lighter than the Dropps pods, which reduces their environmental impact from a shipping standpoint.

As long as you used them with the Dropps Oxi Booster Pods (or some other AOB+activator combo), you’d still end up with hygienically clean laundry. And still lots better off environmentally than using a heavy plastic jug of liquid detergent. And when my box of Dropps runs out, I might actually give these brands a whirl for research purposes.

Not Recommended Laundry Detergents

This is not a comprehensive list. I am only including options that I ran across in my search for specifically plastic free or reduced plastic options.

DIY Laundry Powder

Most of the DIY recipes I have seen involve some combination of the following ingredients:

• washing soda (sodium carbonate/soda ash)
• baking soda (sodium bicarbonate/bicarb soda)
• borax (sodium borate)
• epsom salts (magnesium sulfate)
• sodium percarbonate/sodium carbonate peroxide (usually in the form of “OxiClean” powder, or similar products with sodium percarbonate listed as a main ingredient)

The major argument in favor of doing a DIY powder detergent is cost. These ingredients are found in many commercially available powdered laundry detergents, but are available for much cheaper as individual ingredients, often in easy-to-recycle/ more sustainable/ plastic free cardboard boxes. Washing soda (sodium carbonate) and borax (sodium borate) are two examples.

All that said, I still hesitate to recommend DIY laundry powder recipes for three reasons:

1. I have heard of people’s machines being ruined, despite claims that the recipes are safe,
2. I cannot find a plastic free version of sodium percarbonate (a color safe, activated oxygen bleaching agent; the closest ingredient is OxiClean which comes in a plastic tub), and
3. I cannot find a commercially available bleach activator, and therefore cannot guarantee their effectiveness not only at removing dirt and stains, but also destroying microbes.

For information regarding why activated oxygen bleaches and bleach activators are so important for hygienic laundry practices, jump to “How “clean” do washing machines even get our clothes?” below.

The short story is that for the most hygienic and sustainable laundry, sodium percarbonate and a bleach activator are the two most important elements. If those ingredients are not available, or not available in a plastic free form, you are worse off environmentally than if you bought a commercially available plastic-free versions with both, or even just the sodium percarbonate without the activator.

How often do I need to wash my clothes, anyway?

I don’t want to sound too conspiracy theorist, but in western society we tend to over wash our clothes. I suspect that it has to do with some very good marketing done by soap and detergent manufacturers to change our ideas over what it means to be “clean.”

And of course, the discovery of the relationship between microscopic organisms and disease has only inflamed our fears. The result is we’ve become a bit “hypersterile” and generally overly afraid of all microorganisms because some are “germs.”

The good news for us, though is that new research is showing that our indiscriminate fear of all microorganisms is mostly unfounded, so I’m hopeful that the relationship will shift in the near future. If you’re interested in learning more about microorganisms and the history of our relationship with them, I strongly recommend reading I Contain Multitudes by science writer Ed Yong. He does a really good job of cutting through some of the “hype” (aka junk) science to get to the real stuff, while weaving interesting stories and a new perspective.

The reality is that not all microorganisms are bad, and in fact, it’s only a very small minority that cause humans problems. The rest are poorly researched, but likely beneficial. And if not beneficial to humans, at least neutral.

All this is to say that putting on an article of clothing is not by itself enough justification for putting it through the wash. Or as my darling brother likes to say,

“If it’s not dirty, it’s clean.”

Darling Brother

Might seem a bit self-evident, but I’ve found it to be sage advice. It’s not quite the same to say if it’s not clean, it’s dirty, and therefore in need of washing. It makes me pause to think, “Is this piece of clothing actually soiled, or am I just tossing it in the laundry bin because it’s easier than putting it away?”

Now of course it depends on what you do while wearing your clothes. Went to the gym and got all sweaty, and got exposed to everyone else’s germs too? I’d vote for washing. Wore a shirt to an office job that requires little physical exertion, maybe wear it once or twice more.

My system is if I wear a shirt or dress and don’t spill anything on it or otherwise get it dirty, I hang it back up in my closet inside out. Then the next time I put it on I’ll know I’ve already worn it at least once and should probably put it in the laundry once I’m done wearing it again.

Everyone will have to work out their own system and figure out what they are comfortable with, but the point here is to make sure it’s a conscious decision.

I cover this topic a little more in depth later in this article when I describe Doing Laundry with Activated Oxygen Bleach. Another great resource for determining when and how clothes should be washed is “Appendix 1. Guidance on Machine Laundering of Clothing and Household Linens in the Home Setting” (p. 52) of the International Scientific Forum on Home Hygiene published an evidence-based report in 2013 called Effectiveness of laundering processes used in domestic (home) settings.

In the case for washing less, I’d also like to link to “The Dirty Jeans Manifesto,” an article written by Chip Bergh, President and CEO of Levi Strauss & Co., where he explains his comments at a public talk that lead to headlines of the ilk “CEO never washes his jeans.” He writes,

“How to take care of your very best denim has been a subject of debate for decades, particularly amongst denim aficionados. My point at the conference, which by the way was all about sustainability, was to challenge the mindset that we need to throw everything into the washing machine after one or two wearings…

Finally, we knew that 46% of water consumed happens after the consumer gets the jeans home, and starts washing them. To address this, and give consumers guidance on what they could do to reduce their carbon footprint, we created the “Care Tag for the Planet.” This encourages consumers to be mindful when caring for their Levi’s jeans by washing them less often, using cold water and line drying them…

Imagine the global impact we could make if everyone who wears jeans significantly reduced the number of times their jeans go in to the washing machine? Not only will the planet be better off, but so will your denim!”

Chip Bergh, LinkedIn “The Dirty Jeans Manifesto” 2014

Let’s also take a look at the Business Insider article “Is Not Washing Your Jeans Hazardous To Your Health?“

“There is no evidence that not washing jeans is hazardous to your health, said Bernhard Redl, an associate professor in the molecular biology department at the University of Innsbruck in Austria. That is, when they are worn under normal conditions, such as everyday street wear…

Bacteria, skin cells, and sweat are transferred to our pants from our own body but “skin microorganisms are generally not hazardous to ourselves,” said Rachel McQueen, a professor of human ecology at the University of Alberta in Canada. McQueen’s research focuses on the development and retention of odors in textiles…

A few years ago, one of McQueen’s students wore his jeans for 15 months straight without a single wash and then tested the level of bacteria on them. The student-teacher team was surprised to find that the unwashed jeans carried nearly the same amount of bacteria as those same pants after they had been washed and then worn for another 13 days…

“It is clear that freezing does not kill most of the bacteria,” said Redl, “but puts them in a dormant state.” Bacteria stops growing in the freezer, but will become active again once you slip your pants back on and those germs are warmed up by the heat of your body.

“I think airing your jeans outdoors in the sunlight would be a more effective method of getting rid of odors and a lot of bacteria,” said McQueen.”

Dina Spector, Business Insider “Is Not Washing Your Jeans Hazardous To Your Health?” 2014

Wow, that’s a very dedicated jeans wearer! We should note, however, that the experiment was not a very rigorous one and was not meant to be particularly scientific. I’d love to see a more scientific study performed, perhaps measuring bacteria levels week after accumulated week.

I do find it reassuring that neither scientist mentioned in the article seems to think that not washing is particularly hazardous. I’m not reassured enough to stop washing my clothes altogether, because they do get dirty, but it does make me more comfortable not washing them obsessively or excessively.

We can turn to a scientific study for advice as well: Bockmühl, Dirk P. et al. “Laundry and textile hygiene in healthcare and beyond.” Microbial Cell vol. 6,7 299–306. 1 Jul. 2019, doi:10.15698/mic2019.07.682

“In general, it can be assumed that most of the microorganisms found on textiles should not pose a considerable health risk, as long as these microorganisms are part of either the transient or the resident human skin flora which we are in permanent contact anyway.”

“Since the majority of microorganisms found on textiles are also part of the human microbiome or the environment, they mostly should not pose human health risk.“

“Inadequate laundry hygiene can be a problem for these risk groups including infants, elderly people, pregnant women and, as mentioned before, people with a deficient immune system.”

Bockmühl et al

Alright, so now we know that in general, the microorganisms on our clothes really aren’t as bad for us as we’ve been raised to believe. But there are times when it IS important to get our clothes clean, like when we’re trying to stop actual pathogens from spreading (perhaps on cloth hankies!), or if there’s some funky odor going on, or your clothes actually got dirty, with dirt or a stain. In those times, we want to make sure the washing process is doing the best, most efficient job it can. Because if it’s not, that’s not really sustainable at all!

*** Update March 2020***

There’s been a lot of news lately about the coronavirus/COVID-19, and as someone who is immune compromised (the medicine for my rheumatoid arthritis shuts down my immune system) I think it’s important for everyone to do their best to maintain high standards of hygiene at this time to help prevent the spread of disease.

Part of that equation, in addition to the basics of hand washing, not going to work or public places when you’re sick, etc, is making sure your clothes washing practices are effective at disinfecting your clothes. For more information, please keep reading, or jump to the Efficient Laundry Practices section.

I also strongly recommend reading the International Scientific Forum on Home Hygiene‘s evidence-based report called Effectiveness of laundering processes used in domestic (home) settings. In “Appendix 1. Guidance on Machine Laundering of Clothing and Household Linens in the Home Setting,” (p. 52) they include some really useful guidelines to help determine which clothes need the most hygienic laundering (if you’re sick or think you might be sick this would be all of them!), and the best practices for each level of clean.

***

This leads to another question in the how often should we wash debate:

How “clean” do washing machines even get our clothes?

Bad news for germaphobes (and at-risk populations!) – turns out that most washing actually doesn’t do a good job of disinfecting our clothes after all. I have sifted through a lot of textile hygiene research, and in this section, I’ll be quoting from the highlights. If you want more, be sure to check out the Sources/ Further Reading section for more fun facts and additional articles.

Inefficient Laundering Practices

It’s pretty clear from the scientific literature that while most laundry practices these days might do a decent job of removing dirt from our clothes, they don’t offer much in the way of hygiene or sterilization. We’ll talk first about the evidence for poor practices.

In “Bacterial Exchange in Household Washing Machines,” Chris Callewaert et al write,

“Household washing machines (WMs) launder soiled clothes and textiles, but do not sterilize them.”

“This study revealed that the household low-temperature laundering process created a bacterial mixing in the laundered clothing textiles… By means of the WM, malodour-causing microbial species might be further distributed to other clothing textiles.”

Callewaert et al

In “Enteric Virus Survival during Household Laundering and Impact of Disinfection with Sodium Hypochlorite,” Charles Gerba et al state,

“Washing with detergent alone was not found to be effective for the removal or inactivation of enteric viruses [adenovirus, rotavirus, and hepatitis A virus].”

“It was also demonstrated that viruses are readily transferred from contaminated cloths to uncontaminated cloths.”

“Laundering practices in common use in the United States do not eliminate enteric and respiratory viruses from clothes.”

Gerba et al

In “Laundry and textile hygiene in healthcare and beyond,” Dirk Bockmühl et al note,

“energy efficiency of appliances… has resulted in a general decrease in washing temperatures which in turn can impact the antimicrobial efficacy of laundering.”

“the washing process may cause a shift in the microbial community on textiles from primary contaminants (skin bacteria) to secondary contaminants (biofilm-associated environmental bacteria) and that the water itself can also be a source for recontamination and contribute to secondary contaminations”

“Inadequate laundry hygiene can be a problem for these risk groups including infants, elderly people, pregnant women and, as mentioned before, people with a deficient immune system.”

Bockmühl et al

In another paper, “Laundry hygiene—how to get more than clean,” Bockmühl writes,

“While industrial and institutional laundering employs standardized processes… to ensure a sufficient hygienic reconditioning of textiles, domestic laundering processes are less defined and not always led by purposeful aims.”

“Laundering mainly aims to remove visible stains but should also provide a hygienically clean textile surface, which means that microbial contamination and malodorous substances are removed as well. However, while the successful dirt removal can be assessed visually, the removal of micro‐organisms or malodours cannot be proven that easily.”

“The wash cycle time in programmes that use lower temperatures to improve energy efficiency has been prolonged to ensure the same cleaning result, which has been shown to work well for stain removal (Janczak et al. 2010), but only to a limited extent for the inactivation of micro‐organisms (Honisch et al. 2014).”

Dirk Bockmühl

So from all this it seems pretty clear that using detergent isn’t as effective as we thought at getting our clothes truly, hygienically clean, so what should we be doing instead?

Efficient Laundering Practices

The same Bockmühl article, “Laundry hygiene—how to get more than clean,” is actually a good place to start discussing efficient laundering practice, as he introduces the “Sinner circle”:

“To explain the influence of parameters determining the cleaning performance in laundry, the Sinner circle has long been used and is widely accepted (Sinner 1960). This concept states that the four factors, time, temperature, mechanical action and chemistry, work together in the cleaning process. Each of the factors accounts for a certain percentage of the total cleaning performance and can in principle be compensated by one of the other three. One of the most prominent examples for the application of this concept can be found with the ‘eco’‐programmes of current washing machines that aim to decrease the washing temperatures in order to save energy and exhibit in turn very long programme durations. This has been shown to work very well in terms of soil removal.”

“It has also been established that temperature is one of the most important factors to ensure laundry hygiene. Although it is difficult to differentiate between the Sinner circle impact factors in many of the existing studies it is obvious that a higher washing temperature increases the logarithmic reduction (LR) of micro‐organisms on a textile surface during laundering.”

“Along with temperature, chemistry is regarded as the second most important factor that influences the antimicrobial efficacy of laundering processes. However, the laundry detergents used can be made up of many different components, making it very difficult to estimate the impact of a certain compound or to compare different studies. Nevertheless, there are three major groups of ingredients that may determine the antimicrobial efficacy of detergents: surfactants, bleaching agents and quaternary ammonium compounds.“

“Surfactants as the most important component of detergents account for the basic cleaning efficacy and should remove hydrophobic soil. There are only few investigations that allow observation of this detergency effect of surfactants on micro‐organisms. Honisch et al. (2016) recently investigated laundry processes with and without detergents and found little or no effects when comparing the remaining microbial load on artificially contaminated swatches after laundering in a domestic washing machine.”

“In comparison with surfactants, bleach has to be considered the major antimicrobial active ingredient in laundering processes. The use of bleach, however, varies greatly within different regions of the world. First of all, the term ‘bleach’ may refer to chlorine bleach (sodium hypochlorite) that is traditionally added to the laundry, for example, in southern Europe or the United States. Consumers in other countries, such as Germany, prefer to use AOB [activated oxygen bleach]—mainly peracetic acid derived from perborate or percarbonate and the bleach activator tetraacetylethylenediamine (TAED). In contrast to chlorine bleach, AOB can be formulated into solid detergents using the precursor substances, thus resulting in a product which is convenient to use and provides good cleaning results even at lower temperatures. In special products and in industrial laundering, other oxidizing agents, such as hydrogen peroxide or phthalimidoperoxyhexanoic acid are used as well. This chemical diversity makes it difficult to assess the antimicrobial impact of bleach when reviewing the scientific literature, because many of those studies do not disclose what kind of bleaching agents was used. Nevertheless, nearly all of these investigations show that AOB or chlorine bleach can enhance the antimicrobial activity of detergents significantly.“

“the influence of time and mechanics has not been investigated nearly so intensively. These two parameters have to be considered interdependent, since the prolongation of the wash cycle time results in more mechanical action (but will also increase the influence of chemistry and temperature). Honisch et al. (2014) systematically investigated the effect of main wash times on the antimicrobial efficacy of laundering and found that prolonged main wash times can increase the LR [logarithmic reduction] of the tested organisms significantly, especially when detergents without AOB were used. However… it must be assumed that prolongation of time can only partly compensate for decreasing temperatures as suggested by the Sinner circle.”

“for most of the tested bacterial and fungal organisms (S. aureus, E. hirae, Pseudomonas aeruginosa and Candida albicansbut not for Trichophyton mentagrophytes) it was not possible to achieve a complete reduction using AOB without mechanical action. This means that the removal of microbial cells (mediated by the drum agitation and the physicochemical interaction with surfactants) plays an important role in laundry hygiene also at higher temperatures.”

“Apart from the parameters covered by the Sinner circle, there are numerous other factors that may affect the hygiene efficacy of laundering, none of which has been subject to comprehensive investigation. Some factors that should be mentioned (without intending to be exhaustive) are the type of textile (e.g. cotton, polyester, wool), the soil matrix in which the micro‐organisms are embedded on the fabric (e.g. blood, faeces, food) and the conditions surrounding the laundering process (e.g. drying). There are some indications that these parameters may also play an important role in laundry hygiene. For example, micro‐organisms colonize various types of textile differently.”

Bockmühl

I tried to look up the original article written H. Sinner, but it seems to be in German (“Über das Waschen mit Haushaltswaschmaschinen“), so I had trouble tracking it or a translation down. We’ll just have to trust Bockmühl on this one I guess. To summarize what we just read:

These ideas are echoed in other literature as well. For example, in Impact of wash cycle time, temperature and detergent formulation on the hygiene effectiveness of domestic laundering, M. Honisch et al write,

“The use of AOB‐containing detergents as well as high washing temperatures reduced cross‐contamination to sterile swatches included in the load.”

“The study demonstrates that it is possible to compensate for the loss of hygiene effectiveness of laundering at lower temperatures using detergents with activated oxygen bleach or by extending the wash cycle time.”

M. Honisch et al

In Enteric Virus Survival during Household Laundering and Impact of Disinfection with Sodium Hypochlorite, Charles Gerba et al found that,

“Washing with detergent alone was not found to be effective for the removal or inactivation of enteric viruses.”

“The use of sodium hypochlorite [bleach] reduced the number of infectious viruses on the swatches after washing and drying by at least 99.99%… Laundering practices in common use in the United States do not eliminate enteric and respiratory viruses from clothes. The use of bleach can further reduce the numbers of enteric viruses in laundry.”

Charles Gerba et al

And here in Effectiveness of laundering processes used in domestic (home) settings by Bloomfield et al,

“The data shows that decrease in temperature can significantly increase numbers of survivors on contaminated fabrics, and the transfer of microbes to other items included in the wash. The inclusion of detergent in the wash is associated with a significant decrease in numbers of microbes found on laundered fabrics and decreased transfer of contamination within the wash load. This reduction can be further enhanced where activated oxygen bleach (AOB) is included in the detergent formulation.”

Bloomfield et al

Doing Laundry with Activated Oxygen Bleach

When I hear “bleach” the first thing that comes to mind is a liquid bleach, aka Clorox. This is a chlorine based bleach, also known as sodium hypochlorite. It’s strong, pretty toxic, and for laundry, really only good for whites. If you use it on colored clothes, they lose their color.

But it turns out that sodium hypochlorite is not the only bleach out there – there are others, including color safe bleaches. An example is a hydrogen peroxide, which is “a Generally Regarded As Safe chemical when used as indicated in its diluted form.“

This bleaching property of hydrogen peroxide turns out to be a key part of effective anti-microbial laundering. In Laundry and textile hygiene in healthcare and beyond, authors Dirk Bockmühl et al explain,

“bleaching agents are presumably the most important component determining the antimicrobial activity of the laundering processes. While in America or Southern Europe chlorine bleach has been used traditionally, in Western and Northern Europe activated oxygen bleach (AOB) predominates. AOB is based on perborate or percarbonate, which can release hydrogen peroxide in aqueous solutions. Since this effect requires higher temperatures, bleach activators such as TAED (tetraacetylethylenediamine) are used to induce the formation of peracetic acid, which happens even below 60°C… Various studies demonstrate that the use of AOB significantly increases the antimicrobial efficacy, but the amount of the microbial reduction also varies depending on the tested microorganisms and the used conditions [31, 35, 38].”

Bockmühl et al

Let’s talk for a minute about sodium percarbonate.

First off, it’s not the same as sodium carbonate, aka washing soda, aka soda ash. The easiest way to describe sodium percarbonate is crystalized hydrogen peroxide. Which is good news for us as far as germ killing power is concerned because when exposed to water sodium percarbonate breaks down into hydrogen peroxide and sodium carbonate (aka washing soda, aka soda ash). It’s a simple chemical reaction that is unavoidable, but also color safe. (Also note that sodium percarbonate is the main active ingredient in products like “OxiClean” – this is the chemistry behind it!)

Unfortunately for our purposes, as stated above and according to Wikipedia, “By themselves these bleaching agents are only effective at wash temperatures of 60 °C (140 °F) or above and so are often used in conjunction with bleach activators, which facilitate cleaning at lower temperatures.” The two most common bleach activators are tetraacetylethylenediamine (TAED) and sodium nonanoyloxybenzenesulfonate (NOBS). When the hydrogen peroxide combines with the bleach activators, it forms peracetic acid, another bleaching agent which is more effective at lower temperatures than hydrogen peroxide.

According to FutureFuel Company, who for 30 years have been “the sole manufacturer of NOBS,” “non-chlorinated products, such as sodium percarbonate, produce hydrogen peroxide as a whitening agent. These products are hot-water activated, which can increase energy costs, destroy fabrics and have a negative impact on the colorfastness of the fabric.”

They go on to compare the effectiveness of the different options: sodium percarbonate alone, sodium percarbonate with NOBS, and sodium percarbonate with TAED.

“The chart demonstrates that after one minute, 100 percent of the bleach from the NOBS system is released. The chart also reveals that an alternative bleach activator, Tetraacetylethylenediamine (TAED), approaches 100 percent after 20 minutes at the same temperature [20 C]. This is longer than the typical wash cycle. A bleach detergent with no activator only releases 30 percent of the available bleach.”

FutureFuel Company, “NOBS“, accessed 7/15/19

This is why bleach activators are such an important part of a sustainable laundry routine!

But remember, as we learned earlier, the same level of hygiene isn’t always necessary for all laundered items. Not all microbes are harmful pathogens, and we don’t all share the same risks of infection. For example, I have an autoimmune disease, and to manage it I take drugs that increase my risk of infection because the medicine works by suppressing my immune system. Because my risk of infection is higher, it’s more important for me minimize my risk of exposure to pathogens compared to someone with an intact immune system because it would be so much harder for me to fight off an infection if I did get sick.

It’s more energy efficient to wash at lower temperatures, but in order to get the same level of hygiene, it is necessary to use a bleach activator with activated oxygen bleach.

The International Scientific Forum on Home Hygiene published an evidence-based report in 2013 called Effectiveness of laundering processes used in domestic (home) settings. In “Appendix 1. Guidance on Machine Laundering of Clothing and Household Linens in the Home Setting,” (p. 52) they include some really useful guidelines to help determine which clothes need the most hygienic laundering, and the best practices for each category.

They divide items to be laundered into two main categories, Category A – Higher Risk Items and Category B – Lower Risk Items, as well as a few subcategories.

Just to give you an idea, some Category A items include “Clothing of family members giving care to infected family members,” “Clothing etc. which is heavily soiled e.g. with faeces or vomit, or body fluids (including reusable babies’ nappies),” and “Sports clothing.” Some Category B items include “Those items of normal daily wear which come into direct, significant and persistent contact with body surfaces during normal daily wear.”

There’s no need for me to rewrite their entire guidance here – I encourage you to follow the link and read the guidance for yourself. Bear in mind, however, that, per the report, “This detailed guidance is primarily intended for reference use by hygiene professionals/ infection control practitioners, community workers, professional and consumer media etc. who are called upon to give advice to their patients, or to the public in general.”

Finally, I think it’s worth noting that the report offers some advice regarding the drying of clothes, and that brings us nicely to our next topic:

Sustainable Clothes Drying, or does the sun kill germs and help clean clothes?

Along my zero waste journey I know I’ve seen many variations of a similar claim pop up, that “the sun can clean your clothes.” I haven’t been able to track down all the places I’ve seen the advice, but I wanted to address the idea here, along with provide some information about clothes drying in general.

It turns out the sun as a disinfectant is actually a very old idea, as you can see in this comment from the 1879 publication of the Proceedings of the Royal Society of London:

“This paper is in continuation of, and supplementary to, a previous communication* in which we recorded the first part of an investigation on the effect of light upon Bacteria and other organisms associated with putrefaction and decay. The chief conclusions to which those observations led us were briefly as follow:— (1.) Light is inimical to, and under favourable conditions may wholly prevent, the development of these organisms” 

“On the Influence of Light upon Protoplasm.” Arthur Downes, M.D., and Thomas P. Blunt, Proceedings of the Royal Society of London, Volume 28 Issue 190-195, 31 December 1879

A much more recent scientific study published in 2018 caused quite a stir when it in many ways validated the “folk wisdom” of sunlight killing germs: “Daylight exposure modulates bacterial communities associated with household dust“. They conclude,

“Our experimental and simulation-based results indicate that dust contains living bacterial taxa that can be inactivated following changes in local abiotic conditions and suggest that the bactericidal potential of ordinary window-filtered sunlight may be similar to ultraviolet wavelengths across dosages that are relevant to real buildings.

Fahimipour et al, Daylight exposure modulates bacterial communities associated with household dust, Microbiome, 2018 6:175, https://doi.org/10.1186/s40168-018-0559-4

What was most surprising was that natural daylight proved just as effective at germ eradication as UV light. It is important to keep in mind, however, that just because sunlight can kill germs in dust, this study doesn’t necessarily prove that sunlight kills germs on fabric, too.

Drying in sunlight, however, is also listed as an additional antimicrobial tactic in the International Scientific Forum on Home Hygiene report Effectiveness of laundering processes used in domestic (home) settings mentioned above. It’s included along with “Tumble drying at 40°C or more, for 20 minutes or more” and “Ironing – particularly steam ironing.” They write that,

“Other components of the laundering process such as drying in sunlight (which has a microbicidal effect due to UV light) and ironing (particularly steam ironing or ironing damp) also contribute to reducing the microbial load.“

They provide the following sources for evidence of the effectiveness of ironing, but none substantiating the effectiveness of drying in sunlight:

• Blaser MJ, Smith PF, Cody HJ, Wang W-LL, LaForce FM. Killing of fabric-associated bacteria in hospital laundry by low-temperature washing. J Infect Dis. 1984 Jan;149(1):48-57.
• Patel SN, Murray-Leonard J, Wilson APR. Laundering of hospital staff uniforms at home. J Hosp Infect. 2006;62:89–93.
• Eckert A, Booten Y, Jarchow M, Lucassen R, Nemitz L, Bockmühl DP. Reduction of microorganisms by ironing. Hochschule Rhein-waal University of Applied Sciences. Poster presentation 2012

They also note that “tumble drying is not recommended as a measure to achieve hygiene due to its poor sustainability.”

As far as drying goes, in Enteric Virus Survival during Household Laundering and Impact of Disinfection with Sodium Hypochlorite, Charles Gerba et al also note that,

“Drying for 28 min was not very effective at reducing virus numbers (Table 1). Adenovirus appeared to be affected the most by this process. Interestingly, drying after washing with bleach appeared to have only a small effect on virus reduction.”

In conclusion, tumble drying might reduce microbial load to some extent, but it uses too much energy to be considered sustainable, and its effect probably isn’t worth the environmental tradeoff. Sunlight probably has an antimicrobial effect, but ironing has the most evidence of antimicrobial impact.

Sources/ Further Reading

Laundry Practices

Bacterial Exchange in Household Washing Machines

Callewaert, Chris et al. Frontiers in microbiology, Vol. 6 1381. 8 Dec. 2015, doi:10.3389/fmicb.2015.01381

• “Household washing machines (WMs) launder soiled clothes and textiles, but do not sterilize them.”
• “The laundering process caused a microbial exchange of influent water bacteria, skin-, and clothes-related bacteria and biofilm-related bacteria in the WM.”
• “Nearly all bacterial genera detected on the initial cotton sample were still present in the washed cotton samples.“
• “Although low relative bacterial abundances were found in the cotton samples after laundering, a considerable diversity was observed.”
• “This study revealed that the household low-temperature laundering process created a bacterial mixing in the laundered clothing textiles. An enrichment of a variety of biofilm-forming bacteria was observed in the studied WMs; however, most of these bacteria were washed out with the greywater. The textiles brought into the WM were found to be more important in the determination of the microbiome of the laundered clothes.”
• “It is suggested that the cause for malodour generation in WMs and clothes is related to the bacteria present in the textiles. It is expected that a household WM plays a role in the specification of the skin microbiome of the household family members. A previous study confirmed that cohabiting family members have large similarities in their –especially skin– microbiome (Song et al., 2013). The laundering process can lead to a mix-up of skin- and clothes-related bacteria between clothes of family members. By means of the WM, malodour-causing microbial species might be further distributed to other clothing textiles.“

Impact of wash cycle time, temperature and detergent formulation on the hygiene effectiveness of domestic laundering

M. Honisch, R. Stamminger, D.P. Bockmühl, Journal of Applied Microbiology, Volume 117, Issue 6, December 2014, https://doi.org/10.1111/jam.12647

• “For all tested micro‐organisms, the temperature needed for decontamination depended on washing time and detergent type.”
• “The use of AOB‐containing detergents as well as high washing temperatures reduced cross‐contamination to sterile swatches included in the load.”
• “The study demonstrates that it is possible to compensate for the loss of hygiene effectiveness of laundering at lower temperatures using detergents with activated oxygen bleach or by extending the wash cycle time.“

Microbial survival and odor in laundry

Signe Munk, Charlotte Johansen, Louise H. Stahnke, Jens Adler-Nissen, Journal of Surfactants and Detergents, October 2001, Volume 4, Issue 4, https://doi.org/10.1007/s11743-001-0192-2

• “The odor formed by surviving skin microflora attached to textiles soiled with human sebum and sweat after laundering at 30°C was studied by sensory evaluation and aroma extract dilution analysis. Intensive odor was formed in both cotton and polyester textiles during prolonged drying. Generally, the odor formation in cotton swatches and the bacterial count of the wash liquor from cotton swatches were greater than the odor formation and bacterial count from polyester swatches. Odorants with animal notes (branched fatty acids) dominated the odor profile after prolonged drying.”
• “The study demonstrates that microbial odor formation is a dominating factor determining the odor impression of laundered cotton and polyester textiles dried under slow drying conditions. The initial soiling with aromatic components has an additional impact on the odor profile of polyester textiles after wash, due to strong adherence of odorants during the wash cycle.”

Enteric Virus Survival during Household Laundering and Impact of Disinfection with Sodium Hypochlorite

Charles P. Gerba, Denise Kennedy, Applied and Environmental Microbiology Jul 2007, 73 (14) 4425-4428; DOI: 10.1128/AEM.00688-07

• “This study was conducted to determine whether enteric viruses (adenovirus, rotavirus, and hepatitis A virus) added to cotton cloth swatches survive the wash cycle, the rinse cycle, and a 28-min permanent press drying cycle as commonly practiced in households in the United States.”
• “The most important factors for the reduction of virus in laundry were passage through the drying cycle and the addition of sodium hypochlorite. Washing with detergent alone was not found to be effective for the removal or inactivation of enteric viruses, as significant concentrations of virus were found on the swatches (reductions of 92 to 99%).”
• “It was also demonstrated that viruses are readily transferred from contaminated cloths to uncontaminated cloths.”
• “The use of sodium hypochlorite [bleach] reduced the number of infectious viruses on the swatches after washing and drying by at least 99.99%.“
• “Laundering practices in common use in the United States do not eliminate enteric and respiratory viruses from clothes. The use of bleach can further reduce the numbers of enteric viruses in laundry.”
• “Drying for 28 min was not very effective at reducing virus numbers (Table 1). Adenovirus appeared to be affected the most by this process. Interestingly, drying after washing with bleach appeared to have only a small effect on virus reduction. Bleach had the greatest impact in virus reduction (Table 2), with more than 99.99% reduction after the final rinse. Still, HAV and rotavirus were reduced by 99% after the rinse cycle.”

The potential impact of washing machines on laundry malodour generation

K. Stapleton, K. Hill, K. Day, J.D. Perry, J.R. Dean, Letters in Applied Microbiology, Volume 56 Issue 4, https://doi.org/10.1111/lam.12050

• “The data presented in this study highlight that the environment and odour of the washing machine can lead to cross‐contamination of laundry.”

Laundry and textile hygiene in healthcare and beyond

Bockmühl, Dirk P. et al. “Laundry and textile hygiene in healthcare and beyond.” Microbial Cell vol. 6,7 299–306. 1 Jul. 2019, doi:10.15698/mic2019.07.682

• “The elimination of microbial contaminations from textile is an important aspect of laundering apart from the removal of stains and dirt from used and worn textiles. Although the framework for institutional laundering is well regulated to ensure hygienic cleanliness via the use of e.g. high temperatures and bleaching agents, there are several open points, especially in domestic laundering.”
• “energy efficiency of appliances is a main driver for innovation and has resulted in a general decrease in washing temperatures which in turn can impact the antimicrobial efficacy of laundering. Thus, the different factors influencing the input and removal of microbial cells in the laundering process and possible adverse effects of microbial contaminants in the washing machine and on the textiles as well as suitable counteractions are discussed in this article, focusing on the clinical area but also considering the domestic environment”
• “In this regard, oxidizing compounds, such as chlorine or activated oxygen bleach and temperatures of or above 60°C play a crucial role to ensure an efficient antimicrobial action of the laundering process.”
• “In the past years especially the use of higher temperatures was aimed to be limited, thereby reducing the energy consumption but also taking away a reliable method to control microbial contaminations. As a consequence, it is necessary to gain a deeper understanding of microbiological problems and possible counteractions to be sure to obtain a proper level of hygiene.”
• “In addition, contaminations can originate from bodily excretions. Items such as underwear contaminated with excretions or shirts soiled with microbial species from the armpits are might thus transfer a quite characteristic microbiota to the textile after contact, even though other members of the skin microbiota can also be assumed, but in a lower extent.”
• “the washing process may cause a shift in the microbial community on textiles form primary contaminants (skin bacteria) to secondary contaminants (biofilm-associated environmental bacteria) and that the water itself can also be a source for recontamination and contribute to secondary contaminations”
• “There are several studies reporting outbreaks related to contaminated laundry, mostly associated with bacterial pathogens, although also viruses and fungi may play a role [1]. In general, it can be assumed that most of the microorganisms found on textiles should not pose a considerable health risk, as long as these microorganisms are part of either the transient or the resident human skin flora which we are in permanent contact anyway. However, studies showed that in case of infections with i.e. S. aureus, MRSA (multi-resistant S. aureus) or Clostridium difficile, the pathogens were often present on the clothing of both healthcare workers and patients and bed linens as well. Other species, such as Pseudomonas aeruginosaor Trichophyton mentagrophytes (athlete’s foot) from textiles could be associated with infected patients as well [1, 27]. Outbreaks in clinical settings attributed to textiles have been frequently caused by Bacillus cereus but also by Acinetobacter spp. or Aspergillus flavus[28].”
• “This is of a great concern for healthcare facilities like hospitals but also regarding the increasing number of people being cared for at home. Inadequate laundry hygiene can be a problem for these risk groups including infants, elderly people, pregnant women and, as mentioned before, people with a deficient immune system.“
• “Following the Sinner’s principle, a decreased temperature can be compensated by the increase of one or more other variables (e.g. by extending the wash cycle time). It could be shown that for cold temperatures a longer washing cycle would not completely restore the antimicrobial performance of laundering, while increasing the chemical part, e.g. by using bleach containing detergents might better compensate for the lack of temperature [31].”
• “Nevertheless it could be shown by Honisch et al. that in washing cycles with low temperature and low amount of detergent and additive (without bleach) the mechanic might be an important influence by physically removing cells from textiles [40]. “
• “In contrast, bleaching agents are presumably the most important component determining the antimicrobial activity of the laundering processes. While in America or Southern Europe chlorine bleach has been used traditionally, in Western and Northern Europe activated oxygen bleach (AOB) predominates. AOB is based on perborate or percarbonate, which can release hydrogen peroxide in aqueous solutions. Since this effect requires higher temperatures, bleach activators such as TAED (tetraacetylethylenediamine) are used to induce the formation of peracetic acid, which happens even below 60°C. Peracids can be formulated into solid detergent, thus providing a high microbial reduction during laundering. Various studies demonstrate that the use of AOB significantly increases the antimicrobial efficacy, but the amount of the microbial reduction also varies depending on the tested microorganisms and the used conditions [31, 35, 38].“
• “Still, it can be assumed from existing studies that except for heat-resistant strains, such as E. faecium, most bacteria are inactivated quite well even at lower temperatures when bleach is used [31, 35, 38].”
• “Again, in experimental studies investigating the elimination of fungal pathogens such as Trichophyton and Candida from contaminated textiles it could be shown that AOB and higher temperatures might provide a nearly complete inactivation [31, 37].”
• “Since the majority of microorganisms found on textiles are also part of the human microbiome or the environment, they mostly should not pose human health risk.“
• “Whenever a sufficient level of hygiene must be guaranteed, laundering at higher temperatures (i.e. 60°C) and the use of bleach is recommended. This is especially important in critical cases such as acute infections or if special risk groups are affected. Therefore, the trend towards lower washing temperatures in the attempt of saving energy costs can impair the microbial reduction during laundering and thus must be observed carefully. Lower temperatures might at least partly be compensated by the prudent use of AOB or other antimicrobial compounds. Still, if a particularly high antimicrobial efficacy is required, especially concerning immunocompromised persons, low temperatures and short durations of the washing cycle might not deliver a sufficient antimicrobial effect, even when an AOB-containing detergent is used.”

Laundry hygiene—how to get more than clean

D.P. Bockmühl, Journal of Applied Microbiology, Volume 122 Issue 5, May 2017, https://doi.org/10.1111/jam.13402

• “While industrial and institutional laundering employs standardized processes using high temperatures (i.e. 60°C and above) and bleaching agents to ensure a sufficient hygienic reconditioning of textiles, domestic laundering processes are less defined and not always led by purposeful aims.”
• “The strive for energy efficiency of household appliances has resulted in a decrease in washing temperatures in Europe during the last decades and convenience aspects led to an increased use of liquid detergents that do not contain bleach which in turn impacts the antimicrobial efficacy of domestic laundering.”
• “Laundering mainly aims to remove visible stains but should also provide a hygienically clean textile surface, which means that microbial contamination and malodorous substances are removed as well. However, while the successful dirt removal can be assessed visually, the removal of micro‐organisms or malodours cannot be proven that easily.”
• “Although washing at 40°C instead of 60°C allows for a reduction in the energy costs of almost 50% (Industrieverband Körperpflege‐ und Waschmittel 2014), it has been shown that the complete inactivation of several types of micro‐organisms, such as Norovirus or fungi can only be achieved at temperatures >40°C (Ossowski and Duchmann 1997; Honisch et al. 2014; Lemm et al. 2014).”
• “The wash cycle time in programmes that use lower temperatures to improve energy efficiency has been prolonged to ensure the same cleaning result, which has been shown to work well for stain removal (Janczak et al. 2010), but only to a limited extent for the inactivation of micro‐organisms (Honisch et al. 2014).”
• “there are virtually no investigations on the number of microbial cells and the composition of the microbiota on worn or used textiles in daily life scenarios, but some studies suggest that the microbial count after normal use might be in the range of 10²–10⁴ CFU per cm² (McQueen et al. 2007; Lucassen et al. 2013, 2014).”
• “To explain the influence of parameters determining the cleaning performance in laundry, the Sinner circle has long been used and is widely accepted (Sinner 1960). This concept states that the four factors, time, temperature, mechanical action and chemistry, work together in the cleaning process. Each of the factors accounts for a certain percentage of the total cleaning performance and can in principle be compensated by one of the other three. One of the most prominent examples for the application of this concept can be found with the ‘eco’‐programmes of current washing machines that aim to decrease the washing temperatures in order to save energy and exhibit in turn very long programme durations.”
• “It has also been established that temperature is one of the most important factors to ensure laundry hygiene. Although it is difficult to differentiate between the Sinner circle impact factors in many of the existing studies it is obvious that a higher washing temperature increases the logarithmic reduction (LR) of micro‐organisms on a textile surface during laundering.”
• “Along with temperature, chemistry is regarded as the second most important factor that influences the antimicrobial efficacy of laundering processes… there are three major groups of ingredients that may determine the antimicrobial efficacy of detergents: surfactants, bleaching agents and quaternary ammonium compounds. Surfactants as the most important component of detergents account for the basic cleaning efficacy and should remove hydrophobic soil. There are only few investigations that allow observation of this detergency effect of surfactants on micro‐organisms.“
• “In comparison with surfactants, bleach has to be considered the major antimicrobial active ingredient in laundering processes. The use of bleach, however, varies greatly within different regions of the world. First of all, the term ‘bleach’ may refer to chlorine bleach (sodium hypochlorite) that is traditionally added to the laundry, for example, in southern Europe or the United States. Consumers in other countries, such as Germany, prefer to use AOB—mainly peracetic acid derived from perborate or percarbonate and the bleach activator tetraacetylethylenediamine (TAED). In contrast to chlorine bleach, AOB can be formulated into solid detergents using the precursor substances, thus resulting in a product which is convenient to use and provides good cleaning results even at lower temperatures.“
• “In special products and in industrial laundering, other oxidizing agents, such as hydrogen peroxide or phthalimidoperoxyhexanoic acid are used as well. This chemical diversity makes it difficult to assess the antimicrobial impact of bleach when reviewing the scientific literature, because many of those studies do not disclose what kind of bleaching agents was used. Nevertheless, nearly all of these investigations show that AOB or chlorine bleach can enhance the antimicrobial activity of detergents significantly.”
• “Interestingly, although the TAED‐mediated activation of percarbonate or perborate is temperature‐dependent and should work best at temperatures of above 40°C, an additional antimicrobial effect can already be observed at lower temperatures (Honisch et al. 2014). Likewise, chlorine bleach was shown to enhance the antimicrobial efficacy of laundering by 3–4 orders of magnitude, even at low temperatures (Walter and Schillinger 1975; Christian et al. 1983; Blaser et al. 1984; Smith et al. 1987).”
• “Apart from bleach (AOB or chlorine bleach), quaternary ammonium compounds—mainly benzalkoniumchloride (BAC) and didecyldimethylammoniumchloride (DDAC)—are used as antimicrobial actives for laundering processes. Due to their cationic nature, these compounds are incompatible with anionic surfactants, which, however, can be found in virtually any current market detergent. Therefore, quaternary ammonium compounds cannot be used in the main wash together with the laundry detergent, but have to be dosed afterwards during rinsing, resulting in some consequences.”
• “the influence of time and mechanics has not been investigated nearly so intensively. These two parameters have to be considered interdependent, since the prolongation of the wash cycle time results in more mechanical action (but will also increase the influence of chemistry and temperature). Honisch et al. (2014) systematically investigated the effect of main wash times on the antimicrobial efficacy of laundering and found that prolonged main wash times can increase the LR of the tested organisms significantly, especially when detergents without AOB were used. However, unlike the use of AOB, the prolongation of the wash cycle time did not result in the complete elimination of micro‐organisms on artificially contaminated swatches at temperatures below 50°C. Therefore, it must be assumed that prolongation of time can only partly compensate for decreasing temperatures as suggested by the Sinner circle.”
• “Laundering can help to break the chain of infection transmission in domestic as well as healthcare settings by either removing pathogens from the textile surface or inactivating them by the means of chemistry and temperature. It has been shown that contaminated laundry may pose a possible health risk and may also be a source of other problems, such as malodour.”
• “the prudent use of antimicrobial actives (such as AOB) can help to ensure a suitable antimicrobial action of the laundering process, where this is needed, for example, when household members suffer from relevant infections or when immunocompromised persons are affected.”

Microbicidal Action of Heat, Detergents and Active Oxygen Bleach as Components of Laundry Hygiene

Brands, Britta & Brinkmann, Angelina & Bloomfield, Sally & Bockmuehl, Dirk. (2016). Microbicidal Action of Heat, Detergents and Active Oxygen Bleach as Components of Laundry Hygiene. Tenside Surfactants Detergents. Volume 53 Issue 5. September 2016. https://doi.org/10.3139/113.110464

• “decreasing temperatures in laundry can have a significant impact on the hygiene efficacy of laundering”
• “heat at 60°C contributes significantly to the microbicidal action, while detergent only has limited effects. Activated oxygen bleach strongly enhances the microbicidal action and thus has the potential to compensate for the loss of antimicrobial efficacy due to temperature decrease.”
• “This effect varied with the test strain and the temperature, and further work is needed to determine whether it is possible to achieve a hygiene effectiveness equivalent to that at 60°C across both fungal and bacterial strains.”

Evaluation of the Occurrence and Risk of Microbes in Laundry and Laundry-Associated Surfaces

Nordstrom, Jeanne McDonald. Electronic Dissertation. University of Arizona. 2009. http://hdl.handle.net/10150/194201.

Please note, this document is a 160 page doctoral dissertation. I did not read the whole thing, but it does contain a wealth of information on laundry best practices.

Effectiveness of laundering processes used in domestic (home) settings

Bloomfield SF, Exner M, Signorelli C, Scott EA, Effectiveness of laundering processes used in domestic (home) settings (2013) International Scientific Forum on Home Hygiene. https://www.ifh-homehygiene.org/system/files_force/publications/Effectiveness_of_laundering_IFHreport_21102013.pdf

• “In order to save energy, increasingly over the past few years, home laundering has been carried out at lower temperatures (30-40°C). A key aim of this review is to evaluate whether and to what extent the effectiveness of domestic laundering may be compromised by laundering at temperatures of 30-40°C, as opposed to 60°C. Throughout this report the term “effectiveness” is used to describe this process.”
• “The data shows that decrease in temperature can significantly increase numbers of survivors on contaminated fabrics, and the transfer of microbes to other items included in the wash. The inclusion of detergent in the wash is associated with a significant decrease in numbers of microbes found on laundered fabrics and decreased transfer of contamination within the wash load. This reduction can be further enhanced where activated oxygen bleach (AOB) is included in the detergent formulation.”

This is another long (62 page) report. I did not read every page cover to cover, but I did skim through. The report has a very comprehensive review of the literature, so if you wanted to find and read all of the individual studies related to the effectiveness of different laundry practices, this report would be the place to start.

They also have a very good section on laundering at lower temperatures and provide guidance for best practices for household laundry (see Appendix 1, p. 52).

Bleach activator could lead to greener whites

Kerri Jansen, Chemical and Engineering News, Volume 96 Issue 24, June 6, 2018

Antimicrobial Efficacy of Laundry Detergents with Regard to Time and Temperature in Domestic Washing Machines

Honisch, Marlitt & Brands, Britta & Weide, Mirko & Speckmann, Dieter & Stamminger, Rainer & Bockmuehl, Dirk. (2016). Antimicrobial Efficacy of Laundry Detergents with Regard to Time and Temperature in Domestic Washing Machines. Tenside Surfactants Detergents. 53. 547-552. 10.3139/113.110465.

• “This study systematically investigated the antimicrobial effect of laundry detergents (solid and liquid market detergents) with regard to time and temperature in domestic washing machines.”
• “The used solid market detergent containing activated oxygen bleach provided a way to achieve high microbial reductions in low temperature washing.”

The Chemistry of Stain Removals

The University of Kansas – CHEM 190 course materials, accessed online, July 22, 2019.

Chemistry in Your Cupboard: Vanish

Royal Society of Chemistry, Learn Chemistry, accessed online, July 22, 2019.

Ultraviolet Germicidal Irradiation

Wikipedia – Ultraviolet Germicidal Irradiation

Grandma Was Right: Sunshine Helps Kill Germs Indoors – NPR October 2018

Fahimipour et al, Daylight exposure modulates bacterial communities associated with household dust, Microbiome, 2018 6:175, https://doi.org/10.1186/s40168-018-0559-4

Standard and Guideline Requirements for UVGI Air Treatment Systems, WP Bahnfleth, WJ Kowalski, and J Freihaut, Indoor Environment Center, Department of Architectural Engineering, The Pennsylvania State University 104 Engineering Unit A, University Park, PA 16802, USA