60C held for 15+ minutes should be enough for sterilization. The research paper says they washed at 60C but that the quick cycle was especially poor at sterilization. Other than that I didn’t read the paper closer to see if it was a temperature control problem or not enough time at 60C or something else.
It depends on what you're trying to do. Some bacteria and viruses will survive 60 degrees. There's a reason running a very hot wash (>60C) can quickly get rid of weird smells inside of a washing machine occasionally.
Extra annoying: enabling eco mode (the one that is tested when generating the power usage stats on the sticker for these machines) on some machines will make it run "60 degree equivalent", which usually means "longer but at a lower temperature", which obviously doesn't work for sterilization at all.
Of course, this is rarely an issue for consumers who don't need to sterilize their clothes (except when a family member is sick with some specific illness maybe?). But, for hospital workers, which this paper is about, that's a different story.
Don't get me started on eco! Now with heat pump dryers barely heating to 45c only your washing machine can do the job now. And you need a specific function to hold a higher temperature as back in the olden days.
The 90c cycle is the only one I fully trust to get proper hot but I can't wash everything at 90
I think that they had at least one faulty machine. The 'full cycle' failed on only two machines, 'E' and 'G'; 'E' had an unusually low temperature of about 20c - so probably had a failed heater? (It was 9 years old) 'G' seems to have had the shortest hold time (about 5mins) - so again that might explain it; but why is it so short? Both E and G were Indesits; perhaps they need to build their machines to detect failures.
Still, maybe a failed machine is still a valid test - how many hospital staffs machines are unknowingly faulty?
A quick fix would be to swab staffs clean clothes every so often (or put a test patch in with their washes?) and check it.
The study says none of the machines reached 60C, and 2 out of 6 only heated up for 5-13 minutes. No doubt this is so manufacturers can get the Grade A "energy rating" mandated under EU/UK regulation. (It's even worse for "Eco 60" - that only heats up to about 30C).
