A BBC investigation found bacteria with traces of faeces on the ice served in a branch of a well-known fast food chain. Since most UK restaurants don't have to display their hygiene rating, how can you tell you're not at risk of food poisoning, asks Rob Unsworth.
When you go into a restaurant or a takeaway, you might spot a bright green sticker on the door or the window telling you its food hygiene rating.
It's a very helpful steer on whether or not the standards inside are up to scratch - or at least it should be. But in fact - though you might have assumed otherwise - restaurants are not obliged to display their rating in England, Scotland and Northern Ireland.
In other words, any place that scored particularly badly doesn't have to tell you about it. So short of actually poking your head into the kitchen, how can you tell if a restaurant is clean as a whistle - or no such thing?
Anywhere serving food - from the poshest restaurants, to burger vans, and everything in between - is subject to on-the-spot checks by environmental health officers, with the best standards rewarded with a maximum rating of five.
All scores are available online, on the website of the Food Standards Agency (FSA). But that's little use if you're choosing where to eat on the hoof and don't have a smartphone to hand - when being able to see a restaurant or cafe's hygiene rating may well influence your decision.
On a street in London's Soho with 34 restaurants visited by BBC One's consumer series Rip Off Britain: Food, only nine displayed their hygiene rating.
In February 2016, there were 14,251 food outlets across the UK scoring a rating of just two or below - that's nearly 9% of all premises inspected.
Worse still - 973 of these scored zero on the rating scale - which means they need "urgent improvement".
Among them will typically be branches of some of the country's most familiar names.
Rip Off Britain inspected branches of five well-known chains that had recently received the lowest possible rating, to see if things had since improved.
Undercover researchers visited a branch of Costa in Loughborough, Leicestershire, the Chicken Cottage in Hampstead, north London, a Caffe Nero in Bath, the Wimpy in Basildon, Essex, and a KFC in Birmingham.
The samples were then sent to a lab at Leeds Beckett University for analysis.
While the results in most cases turned up only low or harmless levels of bacteria, that wasn't the case at the KFC branch in Birmingham's Martineau Place - which, only weeks earlier, had temporarily closed for a deep clean following its zero rating.
Find out more
Rip Off Britain: Food is broadcast on BBC One at 09:15 BST on weekday mornings from Monday 25 April - catch up on BBC iPlayer
Samples from all the public areas tested - such as tables, serving areas and doors - came back clean. But in each establishment visited, the Rip Off Britain team had also asked for a cup of tap water with ice, as that can be an good indicator of standards behind the scenes.
And at KFC, the ice was found to have high levels of what scientists call faecal coliforms - germs showing traces of faeces.
Dr Margarita Gomez Escalada, who examined the results at Leeds Beckett University, says: "We found high levels of bacteria in the ice. The presence of faecal coliform suggests that there's faecal contamination either on the water that made the ice, or the ice itself, and so it increases the risk of getting sick from consuming this ice."
KFC says it was "extremely disappointed" by the ice test results. It had "immediately launched an investigation", as well as undertaking "a retraining programme with all team members on our standards for touch point cleaning and procedures".
The restaurant chain adds that following a re-inspection this branch now has "the highest possible mark of five out of five", and it takes "food safety and hygiene extremely seriously".
The other establishments the team visited have also now been re-inspected under the Food Hygiene Rating Scheme, introduced in England and Wales in 2010 - Scotland already had a similar scheme.
This time, environmental health officers gave them scores of either four, or the maximum five.
In Wales, all businesses must by law display the sticker that shows their hygiene rating in a prominent place.
How clean is your local eatery?
The Food Standards Agency provides ratings for restaurants throughout the UK at its website here
Catriona Stewart, head of the FSA's Food Hygiene Ratings Scheme, says the FSA wants the rest of the UK to follow suit, and it's currently assembling the evidence that it hopes will persuade the government to introduce legislation to that effect.
"We need to be able to show that it doesn't have an additional burden on food businesses, and we'll be putting that case to the government," she says.
In the meantime, how can diners eating on the hoof somewhere that doesn't display its hygiene rating get a sense of how clean it is?
John Thornhill, who owns a tapas restaurant rated five in central London, says fresh flowers are usually a good sign - if owners care enough to put them out "there's still some love there".
Also, he suggests: "I would ask your server what their favourite dish is. If you get a response that talks about the latest seasonal changes and how they tried this as a group last week, chances are you're in a good situation. If you get the impression that they never eat there, you probably shouldn't either. "
Food safety and hygiene expert Dr Lisa Ackerley recommends the time-honoured route of checking the loos.
"Go in the toilets, see what it looks like in there, if they can't get that right, I'm sure they won't have got the kitchen right," she says.
Correction: An earlier version of this story incorrectly stated that the BBC team visited KFC after a re-inspection in which it had received the maximum hygiene rating.
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