The bacteria was found at three different McDonald's locations. Justin Sullivan/Getty Images You may want to think twice before ordering a soda at lunch today — or at least skip out on the ice.

A BBC undercover investigation has found fecal bacteria in the ice served at McDonald's, Burger King, and KFC locations in the UK.

The news comes weeks after the BBC discovered that samples of iced drinks from Starbucks and two other UK chains — Costa Coffee and Caffe Nero — contained "varying levels of the bacteria."

The coliform bacteria, which is found in human and animal feces, was discovered in three out of 10 ice samples from McDonald's, six out of 10 samples from Burger King, and seven out of 10 samples from KFC.

The results will be aired Wednesday on the BBC TV show "Watchdog," according to the Liverpool Echo.

According to DEFRA, the government department that sets the water standards for the UK, coliform bacteria should not be present in any water used for human consumption.

In the show, Tony Lewis, head of policy and education at the Chartered Institute of Environmental Health, commented on the findings in the show, according to the Liverpool Echo.

“It’s extremely worrying,” he said. “When we’re finding the sorts of numbers we’re finding here, 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?”

McDonald's told Business Insider that while coliform bacteria was found in the samples, there was no evidence of E. coli bacteria, another indicator of feces contamination.

“Like many UK food retailers, our ice is made by freezing drinking water using commercial ice machines. As the investigation highlights, there are no specific ice production standards in place, only those relating to unfrozen drinking water. We would therefore welcome the introduction of an agreed standard and would be happy to work with relevant industry bodies," a spokesperson for McDonald's told Business Insider.

Burger King told Business Insider: "This report is an opportunity for us to emphasize our training procedures and ensure all operations and safety standards are upheld in all Burger King restaurants."

KFC has shut down the ice machines at the affected restaurants and has inspected and cleaned ice machines in all of its other locations across the UK, a spokesperson for the company told Business Insider.