Ice cubes were riddled with bacteria
Ice served in restaurants and bars is regularly riddled with bacteria, a study has suggested.
Almost half the samples of ice taken by researchers from ice buckets and ice machines had traces of coliform bacteria - which comes from faeces.
E.coli was found in one in 20 samples, say Health Protection Agency experts.
They say that handwashing practices among bar staff needs to improve to lessen the risk of food poisoning outbreaks.
Travel health experts have long stressed the need for travellers to many foreign countries to avoid drinks with ice.
Those who fail to observe this golden rule are often stricken with vicious stomach upsets.
However, this rule has never been extended to drinks served in British bars, clubs and restaurant.
The latest survey, presented to the agency's annual conference in Warwick on Monday, found striking evidence that poor hygiene practices may be putting customers at risk.
Dr Suzanne Surman from its Specialist and Reference Microbiology Division, said: "Ice cubes have been found to cause outbreaks of gastrointestinal disease in the past and to prevent this from happening again, it is important that they meet the required standards."
In 44% of the samples from buckets and machines, tests revealed the presence of coliform bacteria. These are bacteria which are present in the human gut and are passed out in faeces.
In addition 5% of the samples showed traces of the potentially-dangerous E.coli bacterium, and 10% contained enterococci.
Dr Surman said that while none of the strains in itself presented a danger, it was indicative that contamination was an ever-present risk.
She said: "These bacteria are present in the human gut and do no harm, but they are useful to show us whether there is the possibility of faecal contamination.
"For example, when the foodhandlers have not washed their hands properly after going to the toilet, the fact that we have found them present in ice cubes that are intended for human consumption shows us that the hygiene measures observed when handling ice need to be greatly improved if outbreaks are to be avoided."
Dr Monique Raats, a researcher at the University of Surrey's Food, Consumer, Behaviour and Health Research Centre, said that bar staff were not always the highest priority for managers when it came to organising food hygiene training.
She said: "It is still not clear, even if training takes place, how much of that is absorbed and remembered."
Other studies have suggested that at least one in five Britons does not wash their hands after going to the toilet.