McDonald's is in the poo after an investigation into the hygiene of its touch screens found they have traces of faeces on them.
The investigation - which was carried out in the UK and tested the touch screens in eight different restaurants - found that every single touch screen tested contained coliforms, which are found in human excrement.
Touch screens have become commonplace in McDonald's franchises, with many New Zealand restaurants having deployed them in the last few years. It is thought their use streamlines and speeds up the ordering process.
The researchers carrying out the investigation, from London Metropolitan University in collaboration with metro.co.uk, said bacteria can remain on the touch screens for several days. Senior lecturer Dr Paul Matawele says it's clear that cleaning of the machines is not rigorous enough.
"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," Dr Matawele said.
Other, even more dangerous bacteria was also noticed on some screens - including listeria and staphylococcus, the latter of which is highly contagious.
"It starts around people's noses; if they touch their nose with their fingers and then transfer it to the touch screen someone else will get it," Dr Matawele warned.
A McDonald's spokesman told The Daily Mail that its touch screens are "cleaned frequently throughout the day".
"All of our restaurants also provide facilities for customers to wash their hands before eating," the company explained.
Newshub.
