Iced drinks from Starbucks and two other U.K. coffee chains contained "concerning" levels of fecal bacteria, according to a BBC investigation.
The investigation found that samples of iced drinks from Starbucks, Costa Coffee and Caffe Nero in the U.K. contained "varying levels of the bacteria."
Tony Lewis, head of policy at the Chartered Institute of Environmental Health, said that the levels of bacteria found in the drinks were "concerning."
He said the types of bacteria identified are "the source of human disease," adding that "These should not be present at any level, never mind the significant numbers found."
The BBC reported that all three chains -- among the biggest in the U.K. -- said they had "taken action," with Costa saying it had updated its ice-handling guidelines and was in the process of introducing new ice equipment storage.
Starbucks said it is investigating the BBC's claims.