Fecal bacteria was found in three out of 10 samples of iced drinks from Starbucks by investigators on BBC’s “Watchdog” program.
They made the discovery after testing about 30 branches belonging to Starbucks, Caffè Nero, and Costa—the three largest coffee chains in the U.K.
“Cleanliness of tables, trays and high chairs at the chains was also tested,” the BBC reported.
The other chains didn’t do any better. Three of 10 Caffè Nero samples also contained the bacteria and seven out of 10 Costa samples were contaminated.
The revelation is concerning, according to Tony Lewis, the head of Education and Policy at the Chartered Institute of Environmental Health.
“These should not be present at any level—never mind the significant numbers found,” he told the BBC.
The problem seems to be with the ice, rather than the coffee.
Costa told the BBC it had updated its ice-handling guidelines and was in the process of introducing new ice equipment storage.
Starbucks and Caffe Nero said they were conducting their own investigations into the claims.
Fecal bacteria are generally not harmful on their own, but they indicate water contamination by sewage and the presence of harmful bacteria and viruses, according to the U.S. Environmental Protection Agency.
“Since it is difficult, time-consuming, and expensive to test directly for the presence of a large variety of pathogens, water is usually tested for [fecal bacteria] instead,” the agency states on its website.
