How often should you wash your towels, change your toothbrush and chuck your kitchen sponge?

Towels should be washed every few days, at a high temperature (at least 60C), with detergent, says microbiologist Dr Primrose Freestone.

Do not read on if you are eating your breakfast. Especially if you are tucking into your toast in bed. Earlier this summer, an American study found that after just one week of use, your pillowcase can harbour more bacteria than the average toilet seat. Meanwhile, a survey this month suggested that a third of us wash our bathroom towels just once every three months, while nearly 2 million people in the UK do so only once a year.

Pause before panicking, however. Less than 1 per cent of bacteria is dangerous to human health. And of those that are, some germs are killed or die off very easily, says Dr Kelly Reynolds, professor of public health at the University of Arizona. “The Covid-19 virus, for example, dies off rather quickly when it dries out on fabric surfaces,” she says.

Still, other organisms are more stubborn.

“Those that cause stomach flu, for example, are adapted to survive passage through stomach acid,” she says. “These often require hot water wash cycles followed by high-temperature dry cycles and or the addition of chemical sanitising agents to effectively reduce them.”

So just how often should we be cleaning the different textiles in our homes?

The bathroom

Towels – every few days

Do not imagine that, post-shower, your sweet-smelling skin is free from micro-organisms, says Dr Primrose Freestone, associate professor in clinical microbiology at the University of Leicester. As you rub yourself down, you will still be transferring bacteria onto your towel.

If you do not share towels with others, of course, then what is deposited is only bacteria that is already on your body. That may sound benign, but as Freestone says: “Your towel may not dry out properly between uses and it’s likely kept somewhere warm. Both these factors mean the bacteria will grow considerably. Your towel will start to smell quite nasty. But also, when you use it again, you’re going to reinoculate yourself with that bacteria. Even if it’s your own, in high enough quantities, it can cause skin infections.”

If you are sharing towels, you risk passing bugs like norovirus and rotavirus around too, as these can live on towels for days, sometimes weeks.

Freestone advises towels are washed every few days, at a high temperature (at least 60C), with detergent. “Detergent compounds don’t only remove stains but they also detach bacteria and viruses sticking to the fabric,” she says. Washing at a lower temperature? “Iron the towel afterwards. The heat will also sanitise it,” she adds.

Toothbrush bristles – once a week

“More than 50 per cent of toothbrushes have both streptococcal and staphylococcal bacteria on them, as well as the herpes virus and faecal matter,” says Laura Schikkerling, a dental hygienist.

“More than 50 per cent of toothbrushes have both streptococcal and staphylococcal bacteria on them, as well as the herpes virus and faecal matter,” says Laura Schikkerling, a dental hygienist. “I would definitely sterilise my toothbrush bristles once a week – just place the head of your brush in mouthwash or white vinegar overnight. Denture cleaning tablets are another good option.”

Shower curtains – seasonally

A 2021 survey suggested that more than a third of us never wash our shower curtains. Take a close look at yours, suggests Catherine Green, who works for the eco-friendly home cleaning company Smol. Any pink stains on its lower reaches? “It’s a bacteria called serratia marcescens,” Green says. “It feeds on the fats in our soaps, conditioners and shampoos.

“For the vast majority of people, it’s not dangerous to health, but it is unsightly. So throw your shower curtain in the machine every season to prevent mould and bacteria from taking hold. The care label will tell you what temperature it can withstand.”

Biological detergent may have the advantage here: “Bio contains enzymes that can break down the fats from any products you’ve used in the shower,” says Green. “They denature, and stop working, at hot temperatures though, so don’t wash much hotter than 40C.”

Bedroom

Bedding – sheets and duvet every week, pillowcases every three days

Only 28 per cent of all British adults wash their bed linen once a week.

Last year, a YouGov poll found that a quarter of young people wait at least a month before cleaning their bed linen. In fact, only 28 per cent of all British adults wash theirs once a week. Does it matter?

“You’re very likely to have sweat, saliva, dead skin cells and more on your bedding – creating the perfect environment for the growth of bacteria, fungi, viruses and tiny bugs,” says Dr Manal Mohammed, senior lecturer in medical microbiology at the University of Westminster.

It would be impractical in the extreme to wash your bedding every day. But Mohammed recommends airing it each morning: “Simply pull the duvet back to let your bedding breathe.” When you do wash it, temperatures of between 40C and 60C are required to kill the bacteria and other germs, she says.

Duvets and pillows – every six months

A 2011 study of pillows used in London hospitals suggested that after two years of use, up to a third of their weight could be made up of bugs, dead skin and house dust mites and their faeces. The best solution is a pillow protector.

“Pillow protectors are brilliant, as you can chuck them in the wash regularly,” says Green. “I’d clean the pillow itself every six months, checking the care label for temperature instructions.”

Take your duvet to the launderette or dry cleaners with the same frequency, she suggests. Worried about mites specifically? Freezing your pillows for eight hours will shift the blighters.

Mattresses – every three months

“Turn them seasonally to air and to dislodge any dirt,” suggests Green. “Vacuum your mattress before you do, then spot-clean any grubby areas.”

Cold water is best for most stains, she says, “and good old bicarbonate of soda is great for deodorising too – sprinkle it all over your mattress for an hour, then Hoover it up”.

Finally: “Line-dry them outdoors, if you can,” says Green. The UV will kill bacteria and the sun will naturally bleach white bedding. “Make sure they’re bone dry before putting them away too, otherwise you risk mould.”

Sitting room

Dog beds – weekly to monthly

Pet beds can be some of the germiest sites in the home.

Forget Fido at your peril, says Reynolds. “Our study found that pet beds were some of the germiest sites in the home and were contaminated with high levels of general bacteria and faecal bacteria – including E-coli and even antibiotic-resistant bacteria like MRSA.”

How can you decontaminate your dog’s lair? “As a general rule, I recommend washing pet beds weekly to maintain adequate hygiene, but you may be able to reduce this to monthly depending on your individual exposure and risk potentials,” says Reynolds. A hot-wash cycle and a high-temperature dry cycle is best, she suggests.

Rugs – weekly and seasonally

“If you have pets who lie on your rugs, you’ll want to vacuum them several times a week,” says Green. “But a vacuum cleaner may not be able to get deep down into the fibres of a textured rug.” She suggests taking them outside four times a year to give them “a really good bash. I use an old tennis racket.” If your rug is not too delicate, or in danger of fading, leave it in the sun for a few hours to sanitise it. And use the trusty bicarb to deodorise.

Cushion covers – weekly and annually

“I vacuum my cushions, on both sides, every week, to get rid of dust,” says Green. “Then, once a year, I take the covers off, wash them and hang them outside while I spot-clean the inner cushions.”

Curtains – annually

“Wash them during the summer so that you can line-dry them in the sun,” suggests Green. Long curtains that gather dust and pet hair can be tackled more regularly with a sticky lint roller.

Kitchen

Tea towels – every day

“You wash your hands after handling ingredients. You should treat your tea towels in the same way,” says Freestone. A daily 60C cycle is best, “and if you’ve contaminated your tea towel with raw meat, put it straight in the washing machine”.

The way you store your tea towel matters too, if you want to steer clear of food poisoning. One study contaminated tea towels with salmonella. In those that were subsequently left crumpled, the bacteria multiplied. But in those hung out to dry at room temperature for 24 hours, bacteria levels reduced 1000 times over. Leaving yours to dry somewhere hot is even better, says Freestone, while ironing is a good method of battling bacteria too.

Oven mitts – weekly

“Most of the time, the stuff that you’re taking out of the oven is baking hot,” says Green. “The temperature is going to kill pretty much anything it comes into contact with. So unless you’ve spilt something over them, or really got them mucky, a weekly wash is fine.”

Dish cloths – several times a week

“I put my cloths in the dishwasher when I run a cycle,” says Green. “In the meantime, make sure you’re rinsing them thoroughly in hot water after use, and leaving them somewhere they can thoroughly and quickly air dry.”

Sponges – every other day

In 2017, German germ analysis revealed that there are 362 different kinds of bacteria lurking within kitchen sponges, up to 45 billion per square centimetre – a density of bacteria rivalled only by the human intestinal tract.

Thankfully, a 2006 study from the University of Florida showed that microwaving your sponge or scrubbing pad for two minutes at full power kills 99 per cent of all bacteria, viruses or parasites, as well as spores. “People often put their sponges and scrubbers in the dishwasher, but if they really want to decontaminate them and not just clean them, they should use the microwave,” said Gabriel Bitton, a professor of environmental engineering who led the study.

Make sure it is completely wet and free from metal to guard against fires, the researchers added.