We might be being encouraged to cut our energy bills by doing our laundry at lower temperatures – but tests have shown that clothes and bedding washed at less than 60°C could still be harbouring dangerous germs.
Microbiologists carried out tests on items of laundry, half of which had been washed in a typical family washing machine at 40°C, and the rest taken unwashed from the laundry basket.
It found that the washed items contained only 14 per cent fewer bacteria than the unwashed ones.
Dr Pixie McKenna, of the Channel 4 series Embarrassing Illnesses, said she wasn't surprised by the findings.
"Low-temperature washing encourages a 'bacterial soup' inside our washing machines, with germs transferring between contaminated and uncontaminated items in the wash," she told website Femalefirst.co.uk.
"Bacteria and viruses such as influenza and E.coli can survive in the warm, wet environment of a washing machine and spread from item to item."
So she suggests – unless a garment's washing instructions say otherwise – doing laundry at at least 60°C.