Reports of fecal bacteria in iced coffee at chains like Starbucks are a red flag for bigger problems, a scientist explains

To the question, "Would you like anything else with that?" no one answers "fecal bacteria."

Unfortunately, it may be accompanying orders of iced coffee drinks at three coffee chains in the UK anyways, according to a recent BBC investigation.

The BBC reports that it found "varying levels" of the bacteria in samples of iced drinks from Starbucks, Costa Coffee, and Caffe Nero.

Penny Mairoudhiou, a spokesperson for Costa Coffee, told Business Insider, "We were disappointed with the findings, especially as these stores are all rated 'Very Good' with the top hygiene rating of 5."

The presence of fecal bacteria — which can cause diarrhea if ingested — could be a sign that there are nastier germs also present, said Philip Tierno, a microbiologist at New York University.

"Where there are fecal bacteria present it is an indicator that there could be other germs that are pathogenic [or illness-causing] like Norovirus or hepatitis A or Salmonella that can make you sick," Tierno told Business Insider.

It also suggests that workers at the chains are not keeping themselves clean and that they "have dirty bare hands," he said.

In addition to sampling the ice at 30 of the chains, British researchers also studied their tables, trays, and high chairs. London chain Costa Coffee ranked worst out of the three cafes, with seven out of 10 samples "found to be contaminated with bacteria found in feces."

"It is extremely important to us that all our stores operate to high standards of hygiene at all times and we take it very seriously when any store fails to meet these standards," said Mairoudhiou. "Following these results we have taken immediate action to update our ice handling procedures."

Starbucks and Caffe Nero, on the other hand, tested positive for the bacteria in three out of 10 samples.

Starbucks told Business Insider they had begun their own investigation into the findings, and Caffe Nero told the BBC it had also "taken action."

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