Health inspectors in Leicester have revealed that more than half of the city's takeaways are performing poorly in hygiene tests.
About 60% of more than 200 takeaways inspected were marked as "below average" on standard cleanliness tests.
A new rating system was introduced by the city council earlier this year.
Premises are given window stickers with a smile or a frown corresponding to how well or badly they perform but are not compelled to put them on display.
Anyone can access the results of the takeaway inspections on the council's SmileSafe food safety website.
Hygiene tool
Takeaways are given scores from zero to 30 based on food hygiene and safety procedures, cleanliness, lighting and ventilation.
The owner of Grimsby Fish Bar, Lefteris Eleftheriou, said the inspectors looked at cooking temperatures, state of the kitchen and paperwork.
Malcolm Grange, the head of environmental health and licensing at the council, said the pilot scheme focused on takeaways because there was a high turnover and a need for more education in that sector.
"The scheme promotes and recognises good standards. It also highlights under-performing and aims to have incentives to make improvements because the results are made public.
"It is a tool to drive up food hygiene standards in food businesses."
He said that, while there was no obligation to display the food hygiene sticker if the takeaway failed, action was taken if the standards were not acceptable.