Towels can develop a musty smell when households switch on their heating, as bacteria multiply on damp fabric, according to bathroom specialists at Bathroom Fort. The unpleasant odour has been traced to a bacterium called Moraxella osloensis, which can survive washing and multiply when fabrics take too long to dry.
Bacteria found in most smelly towels
Researchers at Japanese consumer goods company Kao, writing in the journal Applied and Environmental Microbiology, found the bacteria in 75% of the smelly bath towels they tested and every smelly hand towel. The bacteria survived both drying and exposure to ultraviolet light, with the distinctive smell developing on towels that had already been used.
This is because the bacteria need sweat and skin oils left behind on the fabric to produce the odour. Slow drying can make the problem worse, particularly when laundry is hung indoors during the colder months.
Slow drying worsens the problem
A separate study by Procter and Gamble scientists, published in the journal iMeta, found that bacteria on freshly washed hand towels multiplied more than 30-fold in a single day when left to dry in damp air. This can become a particular problem during the heating season, when many households dry their washing inside rather than outdoors.
Research by the Glasgow School of Art, which examined 100 homes, found that 87% of households dried laundry indoors between September and May. Of those, 64% dried their washing on or near a heat source. The researchers also found that a single load of washing releases around two litres of moisture as it dries. In poorly ventilated rooms, this can account for up to a third of the moisture in the air.
How to stop towels smelling musty
Faz Salloo, director at Bathroom Fort, said: “Summer towels get a head start, because the bathroom window's open and they're bone dry by lunchtime. Come October the same towel is still damp at teatime, and that's all those bacteria need to get going again, so the smell comes back the minute it gets warm and wet in the shower.”
Research reviewed by scientists at Ghent University found that slow drying leaves more bacteria on fabric. The review recommends fast, consistent drying, ideally outdoors in sunlight when weather conditions allow.
The International Scientific Forum on Home Hygiene recommends washing everyday towels at 30C to 40C with an oxygen bleach-based laundry product. It also advises avoiding quick, water-saving and eco cycles. Fabric conditioner can reduce cotton's ability to absorb water, according to research by Kao. John Lewis advises using it sparingly on towels rather than adding it to every wash, as towels that absorb less water can take longer to dry you properly.
The International Scientific Forum on Home Hygiene also recommends washing items used by someone with an infection at 60C or above. The NHS advises against sharing towels with anyone who has diarrhoea and vomiting. Drying clothes and towels in a closed room can increase moisture levels, creating conditions that encourage mould and dust mites.
