Samples were taken from the new machines that have been rolled out at restaurants across the country – every one of them had coliforms.
Senior lecturer in microbiology at London Metropolitan University Dr Paul Matewele said: ‘We were all surprised how much gut and faecal bacteria there was on the touchscreen machines. These cause the kind of infections that people pick up in hospitals.
‘For instance Enterococcus faecalis is part of the flora of gastrointestinal tracts of healthy humans and other mammals. It is notorious in hospitals for causing hospital acquired infections.’
Unsuspecting diners choose their food on the touchscreens then head to the server to pick up their burgers more often than not without washing their hands.
A screen at one branch was found to have staphylococcus, a bacteria that can cause blood poisoning and toxic shock syndrome.
Dr Matewele said: ‘Seeing Staphylococcus on these machines is worrying because it is so contagious.
‘It starts around people’s noses, if they touch their nose with their fingers and then transfer it to the touchscreen someone else will get it, and if they have an open cut which it gets into, then it can be dangerous.
‘There is a lot of worries at the moment that staphylococcus is becoming resistant to antibiotics. However, it is still really dangerous in places like Africa where it can cause toxic shock.’
Metro.co.uk’s study with the university’s school of human sciences involved swabs taken from eight McDonald’s restaurants. Six in London and two in Birmingham.
Listeria bacteria was found in Oxford Street and Holloway Road branches. It can cause listeriosis which can lead to miscarriages and stillbirths in pregnant women.
Dr Matewele said: ‘Listeria is another rare bacterium we were shocked to find on touchscreen machines as again this can be very contagious and a problem for those with a weak immune system.’
Three quarters of the screens swabbed showed traces of the bacteria proteus.
Dr Matewele said: ‘Proteus can be found in human and animal faeces. It is also widely distributed in soil. It can cause urinary tract infections and is also one of the hospital acquired infections where it may responsible for septicaemia.
‘Klebsiella is also from the gut and mouth, they are associated with urinary tract infections, septicemia and diarrhoea. Some species can infect the respiratory tract resulting in pneumonia.
Dr Matewele added: ‘Touchscreen technology is being used more and more in our daily lives but these results show people should not eat food straight after touching them, they are unhygienic and can spread disease.
‘Someone can be very careful about their own hygiene throughout the day but it could all be undone by using a touchscreen machine once.’
McDonald’s does clean the screens with disinfectant but Dr Matewele said it ‘could not have been strong enough.
‘These bacteria can be on touchscreen machines for days on end. A McDonald’s spokesman said: ‘Our self-order screens are cleaned frequently throughout the day. All of our restaurants also provide facilities for customers to wash their hands before eating.’