The Food Standards Agency's nationwide rating scheme means it doesn't matter if your meal of choice is a cafe sandwich, a spicy kebab or a gourmet dinner in a fine dining establishment - each will be judged using the same system.
The bottom mark of zero means 'urgent improvement necessary' and the top rating of five indicates a 'very good' standard of food hygiene.
There are more than 10,000 website ratings available for public examination from places people can eat or buy food, including cafes, restaurants, supermarkets and delis.
Currently 17 of Northern Ireland's 26 district councils are participating in the new scheme.
They are Ards; Armagh; Ballymoney; Banbridge; Belfast; Castlereagh, Coleraine; Cookstown; Craigavon; Derry; Down; Dungannon & South Tyrone; Fermanagh; Newry & Mourne; North Down; Omagh and Strabane.
However, Carrickfergus and Lisburn Council will continue to use the Scores on the Doors star rating system.
Businesses are not obliged to display their hygiene rating sticker or certificate, so it is up to customers to decide if they want to eat or buy food from there without knowing the hygiene standards.
Michael Jackson, head of food safety and operations at the Food Standards Agency, said he was pleased consumers across the UK now have one hygiene rating system that complies with the law to compare the food businesses in their area.
"Operation of the scheme is a by-product of inspections and we will have more councils on board by the end of the year."
Mr Jackson said previous schemes operated different standards, so it was impossible for consumers to effectively compare them.
Lord Mayor of Belfast Niall O Donnghaile said he hoped the scheme would help shine a spotlight on the high quality of food businesses.