Lab tests carried out on samples from Starbucks, Caffe Nero and Costa found faecal bacteria at 'concerning levels' in ice cubes at three well-known coffee chains. The tests formed part of an investigation by BBC One's consumer series Watchdog.
According to the BBC, faecal coliforms, known to contain pathogens which caused disease, were present on 7/10 ice samples in Costa, 3/10 in Caffe Nero and 3/10 in Starbucks.
According to Tony Lewis, head of Policy and Education, at the Chartered Institute of Environmental Health, ''The bacteria found are opportunistic pathogens - the source of human disease. These should not be present at any level - never mind the significant numbers found.''
Cleanliness of tables, trays, and high chairs at the chains was also tested.
It was not yet clear from which store branches the samples were taken.
The first episode of the new Watchdog programme will air on BBC One on Wednesday at 8 pm.
A Starbucks spokesman said nothing was more important than customer safety and that the company took hygiene 'extremely seriously'.
''We have moved quickly to conduct our own investigation into the claims about the stores,'' he added.
''All employees nationwide have received updated training on our high standards of hygiene including ice handling.''
Responding to the investigations Caffe Nero said, ''At Caffè Nero we take the cleanliness and safety of our stores very seriously. We have a team dedicated solely to ensuring that all aspects of safety are maintained and our stores have detailed and timely cleaning schedules to ensure that they are kept up to standard. These standards are regularly audited by our Operations team.
''Our food safety standards and procedures are signed off by our Primary Authority Partner, Eastleigh Borough Council who also work with us to continuously improve our high standards. All of our staff are trained on these procedures and 99 per cent of our stores are rated as very good, good or satisfactory by their local EHO – making us one of the most highly rated businesses on the high street."