/ Health, Home & Energy

Washing machines – does washing at 60 really banish bugs?

Washing machine

More than a third of Which? members use the 60°C program on their washing machine regularly. But is 60 the magic number when it comes to keeping bacteria at bay? And do washing machines actually reach 60°C?

We asked our members why they choose to wash at 60°C. More than half use this program to wash items like towels and bedding. These are laundry items that are typically associated with germs and for a long time the wisdom has been that we need to wash laundry at higher temperatures if we want to wipe out bacteria.

Normally, we test washing machines using 40°C programs, as modern washing detergents are effective enough to allow people to use 40ºC for almost all their washing needs. Towels and bedding seem to be the exception, due to the perceived advantages of washing at 60.

But can you rely on your washing machine to reach this temperature? And is 60°C actually high enough to kill bugs and bacteria anyway?

Testing top temperatures

We put 12 washing machines to the test and measured the top temperature they reached during a 60ºC  wash and how long that temperature was maintained. Eight of the machines did not get to 60 degrees at all. The lowest top temperature was 43°C.

Most of the machines kept the water cooler than 50°C for the majority of the program. That’s not exactly what you might expect if you’re using the 60°C wash with the hope of keeping your laundry bacteria-free.

Banishing the bugs

Our test results suggest that a typical 60°C wash can’t be relied upon to kill bacteria, especially if your machine only reaches this temperature for a couple of minutes (or not at all).

We asked a microbiologist for advice about ridding laundry of bugs and he explained that the real key to wiping out bacteria is using a good laundry detergent to wash them away. Detergents are much more effective than they used to be at lower temperatures, so even if your machine doesn’t get to 60°C, a good detergent can remove bacteria and viruses.

I very rarely use a 60°C wash at home. I prefer to be as energy and water efficient as I can and use a fast program that washes at 30°C. I used to wonder if I was taking any chances by not using a hotter wash on things like towels and sheets. Now I know that laundry detergent has a major role to play in bug removal as well as stain removal, I just have to always remember to actually put some in the detergent drawer…

Do you wash at 60°C? Which washing machine program gives you the most peace of mind when it comes to keeping your laundry bug-free?


Hi @patricktaylor – We have questioned the wisdom of expecting nurses to wash their own uniforms. The Food Standards Agency has just published a report on norovirus: https://www.food.gov.uk/news-updates/news/2017/16303/new-research-on-preventing-the-spread-of-norovirus

“The environment (context and resources) may also have acted as a barrier to effective uniform washing. In the absence of any understanding around why it might not be appropriate it was simply more convenient to have staff clean their own uniforms unless there were cleaning facilities on site or an existing arrangement with an external cleaner.

“We are a franchise company. If you work in another branch there is laundry service.” (ID235, FHRS4)

Overall, knowledge would appear to be the principal barrier to effective uniform washing. There was very little awareness that it might not be desirable for staff to be responsible for washing their own uniforms. Related to this, there was typically an expectation – social influence – that staff would be responsible for washing their own uniform but this appeared to be primarily a function of a lack of knowledge. Survey data supported the idea of a knowledge gap in relation to uniform washing and norovirus with only around a third (13/37) respondents suggesting that ‘professional cleaning of uniform” helped to mitigate transmission.”

Hopefully common sense will prevail and the administrators of hospitals and care homes will see the need to provide laundry services for all staff in contact with infected patients. If I was in charge I would ensure that staff were disciplined if they took their uniforms off the premises.

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It’s about time that hospitals and care homes did some risk assessments.

Well over to Which? and why they pay so little attention to perhaps the most fundamental reasons for there being a temperature shown at all. Heat is a necessary part of the cleaning cycle where health is concerned and this obviously includes workers in the health sector and many messy manual jobs where earth and blood are involved.

We know for a fact that consumers are being misled by claimed temperatures that have no relevance to the actual warmth of the water used.

It really is very simple. You test the claimed temperatures and show the heated water profile as you did in the magazine in August 2013.

You can explain about optical and hygienically clean. You can point out the machines, and I suspect there will be several that have special hygiene washes and test those. This is a health issue and Which? refusing to test and report is shameful.

P.S. It was this issue in 2013 galvanised me! To either run for Trustee and improve matters or quit an organisation which really seemed to have lost its ethos whilst intent on paying it’s top executive more and more.

If you are a member of the Consumers’ Association rather than simply a subscriber you will have had a letter from me in the last week linking to its changing commercial focus and listing six Resolutions to support. This is really our last chance to change direction from a charity run by businessmen back to its broader based membership and more critical role of business and products.

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There is undoubtedly a need for nurses uniforms and other fabrics that may be contaminated with infectious material to be professionally laundered. Duncan has mentioned the use of autoclaves to decontaminate fabrics. In our microbiology labs, staff working with hazardous organisms had their protective coats sterilised at 135°C before they were sent to the laundry.

While I am strongly opposed to temperatures being shown on washing machine dials and control panels because it creates confusion, I don’t believe that many people are going to go back to routinely washing at 60°C and I can see no need for doing so for most users. Many modern fabrics would be damaged by washing at 60°C.

Longer washing times help wash bugs and allergens out of fabrics, in the same way that they remove dirt. The review by D.P. Bockmühl cited above seems to have missed this point, though it does point out that there are different kinds of ‘bleach’ in laundry detergents, a simple but important fact that is missed in some articles. Maybe there is some need for standardisation of the type of bleach used and and encouraging use of detergents containing bleach when washing underwear. When washing at low temperature it is necessary to do a routine maintenance wash to prevent an accumulation of bacteria and fungi on the internal components of washing machines.

I am a subscriber rather than a member.

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It’s vital that we tackle hospital-acquired (nosocomial) infections and hopefully this will be as part of a comprehensive programme of ‘infection control’, much of which is common sense and straightforward. Clostridium difficile forms spores, which are very resistant to heat, and that’s why we need to use autoclaves to kill some bugs.

Unless people are bringing home uniforms etc. from hospitals or care homes, I don’t think there is much to worry about for those in reasonable health.

For once I’m going to agree with you all. 😉

This is an issue. It is misleading. It is confusing. It is causing issues. It is a health risk. It is a problem for machines and the cleanliness of them. It is leading to the early demise of some.

All because of the immense pressure on manufacturers to be “green” and use less energy and one of the only ways to do that is to game the system.

My sentiment is that the temperature shown on the program should be the temperature achieved, not a rough approximation of the wash result, which is the current position.


Maybe it would be worth making a video that shows that without maintenance washes the inside surfaces of machines can become coated with a sticky layer of body grease and dirt that is full of bacteria and moulds, even in the most immaculate houses. Since these bugs grow when the machine is not in use, the next load could have more bugs after washing. Some are harmless, but some nasty bugs have been found in washing machines.

There’s plenty info on that out there already, getting people to take notice of it is the problem.

And it seems somewhat strange that you need to educate people that what they see and think to be the case really isn’t. 😉


Education can help but whether it is successful depends on various factors and cannot be relied on. A large flashing light reminding users of the need for a maintenance wash might do the trick. If I was a service engineer I would not want to dismantle a machine full of stinking gunge.

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Honestly wavechange, people ignore filter change lights on hoods and fridge freezers so I doubt there’s much hope there. Some sure, but I wouldn’t bet the farm on it.

Duncan, marketing and PR tripe is something I am particularly averse to and have spoken on the topic to that effect on several occasions. Mainly to highlight that most marketing/PR is a load of baloney!


OK Ken, but how many manufacturers actually use a large flashing light to alert users to the need for a maintenance wash? Have you a better suggestion, or is it like baloney marketing and nothing can be done?

A couple tried it I think, limited though. Most haven’t even bothered, many don’t even bother to tell people in manuals, not that anyone bothers to read those anyway, unless they have a problem!

Apathy abound. 😉

It may have some effect but how much, I wouldn’t like to say seeing what we see elsewhere as evidence would suggest it likely wouldn’t have too much of an impact.

And if you prevent use until a certain action is take, put restrictions on or whatever it will invariably lead to complaints and false service calls. The shining example of that being anti-balance where you cannot spin very small or very large loads. Generates lots of hassle.


So ‘nothing can be done’? I had expected that.

It’s not that nothing can be done so much really.

It’s a case of, what do you do that might work and has not got a history of previous failure to do so?


I think most dishwasher users respond effectively to the lights for salt and rinse aid replenishment. There will always be a minority who are disinclined to help themselves. So long as they understand that their warranty could be compromised if they fail to look after their tumble dryer or washing machine properly that’s their look-out [although there could be hazardous implications imperilling others]. I would expect the majority of users to comply with warning lights and act responsibly; that would be a good start.

Users may have seen the consequences of not topping up the salt and rinse aid, so there is an incentive to do so when reminded by a light. There is no obvious sign of the build-up of slime inside a machine and if there is no indicator to provide a reminder then it’s hardly surprising that the need for maintenance washes is overlooked.

If I was a service engineer I would be pushing for action because working with contaminated machines could affect my health.

Sadly not true John.

Many people think, even in very hard water areas, they can ignore those as the all-in-one tablet does it all for them, they don’t need to think about it.

Even if the tabs don’t and, the instructions say so.

You would be amazed. And amazed at how many burnt out heaters and heat pumps we see due to it.


Wavechange – Your concern about nurses is touching but you seem to forget the huge number of people working in the home care area, nursing homes, dustbinmen, working with soil and animals etc.

This I find bizarre and inexplicable “While I am strongly opposed to temperatures being shown on washing machine dials and control panels because it creates confusion,” . Surely people ought to know that the correct washing temperature for that particular wash is being reached .

The August/September? 2013 tests by showing the washing programme profile as in length of duration of heated water etc was one of the most eye-opening items published for ages. If I worked in a “dirty” industry the Beko profile was a stand-out.

Incidentally bed-bugs are becoming more prevalent with travel in Europe and that, research shows, does require high wash temperatures to destroy.

I made a mistake, Patrick. As you will see from my previous comments on the subject I am strongly opposed to meaningless temperatures being shown on dials and control panels. No need for sarcastic comments. 🙂 Even the laundry detergent manufacturers have not caught up with the current standards for washing performance relating to optical tests. This page from the UK website for Ariel, a popular brand of laundry detergent, refers to 60°, and many people will assume that this means 60°C. That is inexcusable.

If you look back at the article in the August 2013 issue of Which?, you will find this statement by an eminent microbiologist: No one would suggest that heavily soiled domestic linens should not be treated appropriately. However, are 60˚C washes necessary for sanitising normal linens? Bacterial spores and some viruses are quite resistant to 60˚C. The major sanitising effect of the domestic wash is the removal – rather than destruction – of bacteria and viruses.

Modern detergents contain an aggressive mix of surfactants which dissolve fats, bleaches that target stains, and, in biological detergents, enzymes designed to dissolve fat, protein and starch glue that binds microbes to the fabrics.

These work much better at low temperatures than years ago, when higher temperatures were necessary to achieve the same results.

Why disregard this information? Washing out dirt also removes bacteria. I would qualify that by pointing out that bacteria in damp fabrics could produce biofilms, in which they are immobilised in a matrix of polysaccharide/protein, but that is unlikely to apply in the case of clothing unless it has been left in a damp state.

Farmers are at risk from infection of wounds by a variety of bacteria that are present in soils, especially those contaminated by organic material such as animal waste. Many are spore-formers and even boiling water will not kill the spores. A well known example is food poisoning caused by rice that has been boiled and kept warm. The boiling activates the spores. It’s important to keep wounds clean and covered when working with soil and to be vaccinated against tetanus.

Back to washing machines, we learned recently that many don’t even wash their sheets once a week, and wearing thick winceyette pyjamas and bedsocks has declined since the introduction of central heating. My main concern about low temperature washing is that machines can become coated with a microbial biofilm that can continue to grow when the machine is not in use.

Thank you, Kenneth. I am sure you are right on the basis of actual experience. I have a naive faith in humans’ inclination to do what they are told. I see plenty of dishwasher salt and rinse aid being bought in supermarkets so I assumed most people were using them. Obviously not. We use them and perhaps that explains why our appliances are in good working order, clean and long-lasting. Yes, there is an upfront cost to using protective additives but I believe it saves money in the long run and keeps the repair man at bay.

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I had not heard of this, Duncan, but have read that a couple of people have died after using nasal irrigation with tap water. It should only be done with water that has been sterilised, rather than tap or bottled water. The amoeba is fairly resistant to chlorination but it seems that occasional increased chlorination is effective at dealing with the problem.

Inhalation of water mist contaminated with bugs is an established route for infection with Legionella species and I well remember the deaths at the Staffordshire hospital in 1985 (having spent a week in the hospital the previous year). Ensuring that water stored in hot tanks is heated adequately makes it unlikely that we will pick up an infection from using a shower. We have better defences (e.g. stomach acid) against eating contaminated food than inhaling water mist.

Whether it is slime building up in washing machines or problems with public water supply, the bugs grow in a biofilm on surfaces, which prevents them from being rinsed away.

Some nasty bugs have been identified in contaminated washing machines, though the potential dangers of not keeping machines clean don’t seem to have registered.

Try dismantling the pipework that runs through your kitchen taking the discharge from your washing machine and dishwasher. You’ll then see real sludge.

I don’t think we have discussed dishwashers but food residues adhering to crockery etc. is just what is needed to make bacteria grow. My dishwasher has settings of 35 and 55°C, which I have not used because they would be great for growing bugs. 🙁 I suggest using the maximum temperature at least once a week. Fortunately, dishwashers have fewer places to accumulate bugs than a washing machine.

The waste outflows from our dishwasher and washing machine go onto spigots on the traps under the kitchen sink and utility room sink respectively. By regularly keeping those traps clean with soda or specialist plughole treatments I hope the slime build-up is minimised. I am also trialling the use of enzymatic drain cleaning sticks in the kitchen sink. They are short sticks that you drop down the plughole into the waste trap. One a month is recommended. The packet says they break down grease, fat and food which cause blockages and bad smells. They use “powerful natural bacteria and enzymes” and keep the drain free-flowing and clean smelling. I cannot tell exactly how effective they are without dismantling the pipework but the sink content runs away quickly when unplugged without any back-surging and makes a satisfying gurgle at the finish. I consider occasional soda and hot water treatment is still a good idea though.

We are reaching that time of year again when the periodicity of the refuse bin emptying is a problem. If holidays or other absences disrupt the fortnightly cycle there can be a nasty niff in the air when you open the lid of the general waste bin, especially after hot weather. I thought a weekly rubbish collection was going to be reintroduced but perhaps I was imagining it. I use a bin sanitiser product which has its own pungent aroma that masks all other odours. I also use a bleach solution spray and hose the bin out after every emptying. I haven’t checked whether visitor numbers have changed but the number of flies has dropped.

That is a very valid point wavechange. What is the hygienic state of washing machines? Where is the research? By all accounts porcelain, steel and plastics can take high temperatures without shrinking! : ) so one might think that there is not a problem.

Perhaps these low temperature settings are a trap for the unwary – perhaps not. Furthermore after the wash cycle are you better off leaving the items in the machine and using them from there or unstacking the machine completely as soon as feasible.

I have no information currently in that area and as I am somewhat busy saving the charity from commercialisation will not have time to search.

Our washing-up machine [which is what I presume you were referring to, Patrick] does not have temperature options – unless the Eco programme runs at a lower temperature; I have never checked because we don’t use it – it’s high heat only and any economy is achieved by selecting the Quick Wash or the Half-Load programme.

I cannot see any advantage in leaving crockery, cutlery, pans and utensils in the dishwasher after they are dry and cooled down enough to be safe to handle. It’s not long before more soiled items have to be placed in the machine so the space is needed. It’s a good idea to turn cups, mugs and bowls over and place them on a towel or cloth to dry their bottoms which can accumulate water; they dry easier while they are still hot.

A dishwasher is likely to have the remains of food in the filter or sump, where bugs will grow when the machine is not in use. I don’t think it’s good design to include low temperature washing unless it is used as a pre-wash to soften food deposits.

In my view, the best way to use a dishwasher is to open the door immediately it is finished its cycle and unload it promptly. If you use cups without much of a depression in the base and place them at a slight angle, using the shelves provided, there should be no need for drying.

I agree, Wavechange. But we’ve got some odd crockery that doesn’t conform to the angles of the racks.

Dishwasher instructions advise regularly cleaning of the filter and outlet – well, ours does. If all else fails, read the instructions.

You pointed out that the discharge pipework can accumulate sludge, Malcolm.

I did, and it does. However I was pointing out you should regularly clean the dishwasher filter as the instructions say. Our pipework carries both washing machine and dishwasher discharge and sludge will settle out in its journey, which is some distance from the drain. I am not keen on using chemicals, nor sure about their effectiveness, so from time to time I dismantle the pipes and give them a thorough clean. Those who have appliances next to their sink, with fast outflow through the pipes, may well not have this problem.

I don’t know much about drains but my dishwasher and washing machine discharge into sink drains and in other houses that I have lived in either had the same arrangement or a separate waste pipe with trap, discharging through an outside wall. I do not know if dishwashers have a valve to prevent back flow of waste water.

My concern was about low temperature settings on dishwashers, and programmes such as ‘eco’ which might allow accumulation of bugs in the innards of the machine.

I do clean the biological warfare region that masquerades as a reservoir drain on our dishwasher, but I can’t get right into it, so I compromise by sometimes doing a very hot dishwash cleaner run (Sainsbury’s do a nice fragrant one). But in the hot weather I run a wash daily. Otherwise, I have to admit I usually run the thing on a 50C wash. Perhaps I should use 75C regularly?

Let me put it this way…

I run three programs on a dishwasher, commonly the “heavy wash” which will be at least 65˚C or higher, an occasional pot wash program on mine that’s 75˚C and a rinse/hold.

I never, ever use the low temperature washes or eco, the temp is too low IMO.

A cleaning program with a proper cleaner does work and does help remove a lot of gunk from inside but there will still be areas that need manual, good old fashioned elbow grease. Like the filter where bits of food etc get trapped and around the lower door seal and inner door panel.

Pipework issues are rare to see. Possible, but rare and often a result of poor plumbing more than anything else.


I await the arrival of the mythical but sensible CAwiki which will mean all this information is curated and easily found at a safe resource …… ooh and could it be run by a consumer body!!??


There is more.

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I assume the purpose of a dishwasher rinse/hold programme is to spray the bacterial soup from the sump plus extra water on the crockery, leaving everything wet to encourage growth of bacteria. I thought rinse/hold programmes had been phased out.


It is intended to keep the dishes “wet” so that stuff doesn’t bake onto them, like the impossible to remove Weetabix residues.

The use is, put in breakfast dishes, ran rinse hold. Put in lunch dishes, run rinse hold. Put in dinner dishes, run a full cycle and clean all in one program.


It seems a perfectly sensible programme to stop residues drying and being much harder to remove. Clean water is sprayed around the machine to wet the contents. No different to leaving a used casserole dish to soak in your washing up bowl. Don’t leave either of them for too long of course.

Sorry but I’m right, and if you do some bug counts you will be able to confirm that in the absence of dishwasher detergent, bugs will grow rapidly in water or a damp environment where nutrients (such as food residues) are provided.

If we use this programme it will then be put onto a normal wash within a very few hours. Is there evidence that this procedure will damage health when the dishes are washed and dried normally?

There is no doubt whatsoever that bugs will grow on food residues in a damp environment and in food-contaminated water at the bottom of the machine. The extent of growth will depend on temperature and how long the delay is. What if the user leaves the machine for a day or longer before using a low temperature cycle? I used to grow bacteria in large quantities for research purposes and would rather not do this at home.

A good proportion of dishwashers you see in the field, you’ll quickly come to realise that is the least worry many people have and not a major concern. 😉


Please tell us more. I may regret this. 🙁

Let’s just say that many people seem to think that a dishwasher is really a waste disposal unit supersized. Some of the things you see in the field you honestly would not believe.

After a few days of being bust that can be, to be polite, turn somewhat rancid.


It must tend to provide a jaundiced view, as you obviously see all the worst cases.

I don’t know why some people don’t scrape food off plates before letting a dishwasher see them. The bad smell will be largely due to a rather large number of bacteria.

In part that is indeed true Ian as obviously the ones less cared for are probably more likely to break.


Our dishwasher doesn’t have a rinse/hold programme. We scrape and wash off any food from plates and pans etc unless we are going to start the washing up programme immediately. I drain the filter periodically but there is rarely any gunge in it. We also use a proprietary cleaner from time to time to give it a good splurge.

I thought that rinse/hold programmes had been phased out. I scrape off food and generally use the 70°C cycle, which does a good job. I use an occasional kettle of boiling water to help keep down the bug count and use a piece of plastic to keep the door slightly open when the machine is not in use.

My washing machine has a 40°C quick wash cycle lasting 20 minutes, over half of which is spent rinsing and spinning. My dishwasher has a 35°C quick wash programme. I question the competence of the designers for providing these options, but maybe I have missed something.

If someone from Which? will kindly allow the link, it’s all explained here:



Thanks Ken. Even if we blame the EU for the energy ratings, I don’t believe it is a requirement to produce machines that can achieve the best ratings. Perhaps responsible manufacturers could point out in their marketing why their machines don’t offer a fast wash. I must have a look to see what Which? has to say about fast washes.

In large part it’s consumer pressure.

People want machines that are supposedly cheaper to run, even if the real world difference is really negligible in the grand scheme of things. But it is one of the top three deciding factors on what machine to buy in all sectors so, it’s hugely important to manufacturers and retailers that the machines they sell have the best energy efficiency rating possible.

And, that’s even if it might not be the truth, whole truth and nothing but the truth m’laud.

Then atop that there’s pressure from government (EU, UK, US… whatever) to use less energy to reduce the carbon footprint.

They all just play the game.

To my knowledge from the early 00’s there was some form of agreement that no machine would be produced that offered anything lower than a “C” rating. Today you’ll struggle to find one that is less than an “A” or “A+”.

You’ll also struggle to find many that hit the temp they’re supposed to for as long as they should do and can actually complete a normal wash in less than about two hours.

That’s progress for you. 😉


I am afraid to say (no, i’m not 🙂 ) that energy efficiency is not top of my list when buying an appliance. I want it to do its job properly, be robust and last well.

And I wanted to share this with you as this lady summed it up and encapsulated brilliantly in two short paragraphs on UKW why this is a big problem:

“I think this is shocking. I garden a lot and there is a lot of cat poo from neighbouring cats. I was told that washing affected clothes at 60 would kill any toxoplasmosis germs. Now I am reading that machines don’t reach these temperatures, how am I supposed to be sure of killing the germs? I can’t just use 80/90 or 100 as the clothes are mainly sythetics and it would ruin them.

Not to mention people using washable nappies. They might think they are cleaning at 100 but instead they will be contaminating everything with faeces!”


Bilal Khan says:
22 July 2017

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Patrick Taylor provided this link to the abstract of an article entitled: “Impact of wash cycle time, temperature and detergent formulation on the hygiene effectiveness of domestic laundering.” https://www.ncbi.nlm.nih.gov/pubmed/25207988 Unfortunately the full article is not yet publicly available. 🙁

This is the best article I have seen on the subject and I’m glad to see reference to wash cycle time, though there is no statement to highlight the fact that bugs can be removed by the washing action, just like dirt. Of course longer washing time will also increase the effects of higher temperature and active oxygen bleach. It might have been better if the work had not been commercially sponsored, but this is acknowledged. The authors have provided a detailed methodology that makes it easy to understand the experimental work and should allow other researchers to repeat the experiments.

The abstract is publicly available and summarises the main results and conclusions well:

Aims: Investigation of the effect of temperature and duration of the
laundering process with and without activated oxygen bleach (AOB)-
containing detergent on the hygienic effectiveness of laundering.

Methods and Results: Cotton test swatches were contaminated with
Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa, Candida
albicans and Trichophyton mentagrophytes and were washed in a household
washing machine using temperatures between 20 and 60°C and different
wash cycle times. The logarithmic microbial reduction factor and
cross-contamination (i.e. transfer from contaminated to sterile swatches) were
used to indicate the hygienic effectiveness of the washing process. For all tested
micro-organisms, the temperature needed for decontamination depended on
washing time and detergent type. Hygiene effectiveness of laundering was
enhanced by inclusion of AOB even at lowest temperatures, except for
C. albicans, which was virtually unaffected by AOB. The use of AOBcontaining
detergents as well as high washing temperatures reduced crosscontamination
to sterile swatches included in the load.

Conclusions: Depending on the type of organism, longer wash cycle times or
the use of AOB-containing detergents can be used to enhance the hygiene
effectiveness of laundering.

Significance and Impact of the Study: 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.

It is commonly recommended to wash hygienically sensitive
textiles such as underwear, bed linens, towels and dish
cloths at high temperatures and with a detergent containing
activated oxygen bleach (Wagner 2010; Stiftung Warentest
2013) to reduce potential infection risks in private households.
In recent years, there has been a continuing trend to
apply lower washing temperatures (≤40°C) in German
households (Stamminger and Goerdeler 2007; IKW 2013).

Significance and Impact of the Study: 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.

Conflict of Interest
This study was funded by Miele & Cie., LG Electronics
Deutschland GmbH, Bosch und Siemens Hausger€ate
GmbH, Electrolux Italia S.p.A. and Bauknecht Hausger€ate

@malcolm-r – The article found by Patrick refers to a standard: “Tests were carried out following IEC60456 methodology (IEC60456-2012).” I wondered if you had access to this.

I would be interested to know if it specifies the composition of the laundry detergent(s) to be used in tests and whatever it says about temperature and time specified for tests.

@patricktaylor – You might be interested to know that the test washing machine (Miele W 5000 WPS Supertronic, drum size: 60 l) remained at over 55°C for over 45 minutes during the wash cycle. It looks as if only one machine was tested, but the authors make it clear that more detailed studies are needed.

It’s a good paper but does not look at the possibility of contamination from the biofilm that is likely to coat the inside of a machine unless maintenance (high temperature and bleaching agents) is done to prevent it. As pointed out in the abstract, German users are using low temperatures, as most do in the UK.

One problem that has been mentioned before is that many modern fabrics would be damaged by use of high temperatures and bleach.

I was fascinated to learn that the researchers used small wireless battery operated temperature sensors not much thicker than a coin cell to monitor the temperature during the operation of the machine.

That is excellent news and suggests that the 55C marker is a common test marker as it was the one quoted in 2013 when in the magazine Which? showed some graphs. Beko was the best of the bunch in respect to high temperature and long period.

Miele were not shown but I have respect for their products and durability values. I am about to buy some more of their kit as we are exploring the labour saving devices for our dotage. This covers rotary and steam irons. Also robot cleaners. The iroomba 980 has been very impressive in disappearing under beds and wardrobes and bringing back serious amounts of dust every few days.

I brought up the matter given the new albicans virus illustrates how we need to recognise that hygiene capable machines are very necessary, particularly for those dealing with the ill. There is no real argument that temperature , bleach and duration are important in specific circumstances and this faffing around telling consumers that Which? only tests for optical cleanliness at “40C” is not acceptable if it does not also talk of hygienic cleaning with the same machine.

I would dearly love that Which? actually showed the graphs so people could make informed choices taking into account there personal circumstances.

Incidentally one of my sources points out that plastic drums provide a better site for biofilms to grow – a bonus not much trumpeted in the advertising.

It is relevant that low temperature washing is recommended for a great deal of clothing. Underwear is, I imagine, most likely to be contaminated by pathogenic bugs. Have a look at your wife’s knickers – and your own – and the care label will probably say to wash at 40°C. There is likely to be instructions not to use a laundry detergent containing bleach on dark-coloured fabrics. It’s not good but do any of us have experience of transfer of infections due to using washing machines?

We are both interested in these issues but my greatest concerns are:

1. Users failing to follow instructions and carry out maintenance washes. That will allow bugs to grow inside the machine, out of sight, whether the drum and tub is plastic or stainless steel.

2. Short washes at low temperature are common and popular with users. My Miele ‘washes’ for 20 minutes at 40°C and I believe that others do the same. It might not be long before most of us are ‘washing’ at room temperature.

3. The continued misrepresentation that 60, 60 cotton or 60°C means 60°C. Some manufacturers have removed these labels from their machines and that’s a step forward.

Hopefully Malcolm will be able to provide us with information about the standard tests but I thought that cleaning performance was specified in standards rather than temperature, according to what we have discussed earlier. I wonder if the group responsible for standards has any medical microbiologists in it.

I do believe we are heading for problems and possibly the need for revised standards. Few members of the public will understand the synergistic (combined) effect of time, temperature and bleach in detergents, so I strongly feel that specifications should be laid down by experts and manufacturers follow them.

Well, I’ve looked at BSEN 60456:2016″Clothes washing machines for household use – Methods of measuring performance” which is 204pp packed with info – so I have not done more than a quick skim through. At first sight its objective seems to be to check performance in accordance with the EU regulations for energy labelling, and its effectiveness in cleaning and drying fabrics. My first impression is it seems to be outcome-based rather than the means to achieve it. So at different programmes the results from the test machine are compared with those from a “reference” machine by, for example, measuring the reflectance of washed soiled test pieces. The reference machine specifies water temperature and wash duration for different standard programmes, but I cannot see a test machine being measured for these parameters. It may be that if the test machine gives the required cleaning outcome at its 60 cotton programme, for example, when compared with the reference machine that runs a reference programme including at 60C for x minutes, then it is job done.

However, I am not an expert and have not studied all details and I could be wrong.

@patrick do Which? know whether a manufacturer’s programme requires the achieved water temperature and agitation duration (for example) to be measured for compliance with any standard? I presume Which? test washing machine performance in accordance with the relevant standards.

If not, please let me know and I will ask BSI if you like.

Thanks very much, Malcolm. It would be good to find out if there is reference to use of a particular laundry detergent. The paper I’m looking at gives some detail including the amount of AOB (active oxygen bleach) present.

The detergent used is a “reference detergent A” comprising 77% base powder with enzyme and foam inhibitor, 20% sodium perborate tetrahydrate, 3% bleach activator tetra-acetylethylenediamene. I can list all 13 components of the base powder if necessary.

Thanks again. The paper references an earlier version of the standard: “To ensure that the results can be compared with previous studies, all tests were performed according to established methods (Block et al. 2001; Gebel et al. 2001; IEC60456-2012)”

“The dosage of detergent was adjusted to the water hardness of 1172 mmol l1 by interpolating the dosages for hard water (25 mmol l1; 112 g of AOB-containing detergent) and soft water (05 mmol l1; 75 g of AOB-containing detergent). 874 g of AOB-containing detergent was used. The AOB detergent was composed of 673 g of Detergent A* base powder (wfk Testgewebe GmbH, Br€uggen, Germany) as specified in IEC60456, 175 g of sodium perborate tetrahydrate (wfk Testgewebe GmbH, Br€uggen, Germany) and 26 g of tetraacetyl ethylene diamine (TAED, wfk Testgewebe GmbH, Br€uggen, Germany). In case of AOB-free detergent, 673 g of Detergent A* base powder was used. Before the first test, the ballast load was steam-sterilized and a 95°C washing programme was carried out. After each test run, the ballast load was dried in a tumble dryer (Gorenje D7560A+, Munich, Germany) and a 95°C washing programme was carried out in the washing machine.”

Copy/paste has messed up some of the formatting but the meaning seems clear.

The authors are clearly aware of the relevant standard, which has been updated prior to publication. Unfortunately, the laundry detergents used in the testing are likely to be different from those we buy. The MSDS will show chemicals that would be dangerous in concentrated detergent but not the concentration.

Being a demanding child, I wonder if the committee responsible for the upkeep of the standard includes microbiologists.

CPL/59 is the responsible committee and this is a list of their membership:
A M D E A – Association of Manufacturers of Domestic Appliances
Chair – CPL/59/13
B E A M A Limited – Energy
B E A M A Limited
Co Opted
Chairman – CPL/59/13
Campden B R I
Chairman – IST/6/-/12
Consumer and Public Interest Network
Automatic Vending Association of Britain
The Catering Equipment Suppliers Association
Intertek Testing and Certification Ltd
B E A M A Ltd – The Electric Heating and Ventilation Association
T E H V A – The Electric Heating & Ventilation Association
Microwave Technologies Association
Liaison – IST/6/-/12
SEAMA (Small Electrical Appliance Marketing Association)
D E C C – Department of Energy and Climate Change
Chair – CPL/59/1
Chair – IST/6/-/12
Chair – CPL/59/6
Committee Secretary
BEIS – Regulatory Delivery
Royal National Institute of Blind People
Automatic Vending Association
Committee Chair

Thanks. The most likely possibility of having microbiologists on board is Campden BRI, the service that does campylobacter testing of chicken among many other things.

In my view there is a major problem with domestic washing machines being used to wash nurses’ uniforms. I trust that this is not allowed where staff are working with patients with serious infections that are now difficult to treat thanks to increasing resistance to antibiotics. I might pay a visit to my old department and try to find out more.

malcolm – Which? test regime is to run a standard washes and it is somewhere on the site. The measure is of course optical cleanliness. There was a commercial consumer site in the UK that used to show the before and afters of each stain for each machine which was sort of interesting as for some stains they all seemed equally bad.

Just for some background.


Academics have called for national guidelines on washing nurse uniforms, after research revealed almost half of hospital staff are failing to clean them at temperatures hot enough to kill most bacteria.

Researchers from De Montfort University in Leicester found 49% of hospital staff did not wash their uniforms at the recommended 60°C temperature. They surveyed 265 hospital staff at four East Midlands hospitals.

“The study highlights the importance of research in this area to determine… whether a return to in-house laundering is the most appropriate solution”

The Department of Health released guidance in 2010 stating that uniforms should be washed at the highest temperature suitable for the fabric and that a 10-minute wash at 60°C is sufficient to remove most microorganisms.
However, the temperature requirements set by each hospital varied, ranging from a minimum of 50 degrees to 75 degrees.

The study also revealed that many staff were failing to follow guidelines across a range of others areas in relation to cleaning their uniforms, which the researchers said could increase the risk of spreading healthcare-associated infections.

It found varying and “imprecise” advice was being provided between hospital trusts, which may be adding to confusion for staff who move to different organisations. To tackle this inconsistency, the researchers have also recommended uniform washing is moved back to hospitals, rather than workers doing it themselves at home.

The study found that 40% of those surveyed were cleaning their uniforms with everyday clothes, although there were differences between different departments. Staff working in infectious areas – such as surgical wards, critical care units and emergency departments – were more likely to launder their uniforms separately than those in non-infectious departments.

Again, the hospital guidelines varied, with two stating that uniforms should be washed separately from other items and the other two providing no set requirement.
Meanwhile, around three-quarters of respondents said they cleaned their uniforms following every shift, while 23% reported only changing their uniform after every other shift. In addition, 3% said they changed their uniform after three shifts or more.

This is despite guidelines set by three out of the four hospitals stating that uniforms should be changed daily. Two thirds of respondents either rarely or never tumble-dried their uniforms, which is against three of the hospital’s guidelines which recommend tumble-drying or drying quickly, added the researchers.

The study also found uniforms were commonly – in 78% of cases – used for more than 18 months before being replaced. The researchers concluded that “the DH guidelines that have filtered down to hospital trusts are imprecise”.
“The development of national guidelines for domestic laundering of healthcare uniforms would ensure greater clarity for staff on how to launder their uniforms, especially when transferring to a different hospital trust,” it added.
Report co-author Kate Riley, a PhD student at the university, said: “The study highlights the importance of research in this area to determine the overall effectiveness of domestic laundering and deciding whether a return to in-house laundering is the most appropriate solution.”

From 2011 and inaccurate I think regarding the UK:


Here is the guidance produced by the Department of Health in 2010: http://webarchive.nationalarchives.gov.uk/20130124054344/http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/@dh/@en/@ps/documents/digitalasset/dh_114754.pdf

It is up to the Department of Health to ensure the safety of those working in hospitals and care homes. Hospital laundries have been in use for many years and it concerns me that staff could be taking home uniforms contaminated with hazardous organisms.

I am more interested in the issue from a consumer’s point of view. What is the risk that a family member could pass on an infection as a result of laundering clothing and bedding?

My Miele washing machine takes 3 hours and 29 minutes to complete a cycle on the setting marked 60°C. It might not kill as many bugs as if it was on the 60 cotton cycle which takes 1 hours 59 minutes and reaches at least 55°C, but the long washing cycle will help to wash them out – as with dirt.

If there is a demonstrated need for a specific combination of wash time/temperature/bleach then that needs to be set down in the relevant standards.

From the Deparment of Health document:

Washing uniforms and workwear

All elements of the washing process contribute to the removal of micro-organisms on fabric. Detergents (washing powder or liquid) and agitation release any soiling from the clothes, which is then removed by sheer volume of water during rinsing. Temperature also plays a part.
Scientific observations and tests, literature reviews and expert opinion suggest that:

• thereislittleeffectivedifferencebetweendomesticandcommerciallaunderingintermsof removing micro-organisms from uniforms and workwear;

• washing with detergents at 30°C will remove most gram positive micro-organisms, including all meticillin-resistant Staphylococcus aureus (MRSA); and

• a10-minutewashat60°Cissufficienttoremovealmostallmicro-organisms.Intests, only 0.1% of any Clostridium difficile spores remained. Microbiologists carrying out the research advise that this level of contamination on uniforms and workwear is not a cause for concern.

The standard in question is entitled: “Clothes washing machines for household use – Methods of measuring performance”. There may be a linked standard relating to the effectiveness of machines in removing or killing bugs but I have not seen reference to this. The article provided by Patrick does not refer to it. Perhaps in future, machines will have to meet requirements for removal of bugs. However, physical removal of bugs is obviously related to the cleaning performance that is covered by the existing standard.