In June, an undercover investigation by BBC found traces of faecal coliform bacteria in drinks sold by UK’s top three coffee chains — Starbucks, Caffè Nero, and Costa Coffee.

Faecal coliforms, which contain several disease-causing pathogens, can cause ear infections, dysentery, typhoid fever, viral and bacterial gastroenteritis, and hepatitis A. E. coli is a type of fecal coliform bacteria commonly found in the intestines of animals and humans.

A recent undercover investigation by BBC has now detected faecal coliforms — found in human and animal feces — in ice used in beverages sold by UK’s top three fast-food chains:  McDonald’s, Burger King, and KFC.

Experts tested 10 samples at each of the fast-food chains. The faecal coliforms were discovered in three samples of McDonald’s drinks, six of Burger King, and seven of KFC.

Responding to the findings, a KFC spokesman said:

“We are shocked and extremely disappointed by these results. We have strict procedures for the management and handling of ice, including daily and weekly inspections and cleaning of the ice machine and storage holds, as well as the routine testing of ice quality across our business.

We immediately shut down the ice machines in the restaurants affected to conduct a thorough clean and inspection, and reinforced the importance of adhering to our strict procedures to all employees.”

Burger King ensured strict action saying:

“Cleanliness and hygiene are a top priority for the Burger King brand. The strict procedures we have in place are designed to ensure all guests have a positive experience each time they visit our restaurants.”

A McDonald’s spokesman told CNBC:

“We have robust procedures in place with regard to the production, storage, and handling of ice in our UK restaurants. Nothing is more important than the safety of our customers and people, and we will continue to review our procedures and training, working closely with our restaurant teams to ensure those procedures are adhered to at all times.”

The findings are worrying, the experts say. Tony Lewis, head of policy and education at the Chartered Institute of Environmental Health, commented:

“You have to look at the people making the ice, handling the ice, which they then transfer into customers’ drinks. And then you also have to look at hygiene failure with potentially the machines themselves: are they being kept clean?”

Is the presence of faecal coliforms in drinking water normal? The Department for Environment, Food & Rural Affairs, a UK government body responsible to set water standards, says coliform bacteria should not be at all present in water used for human consumption.