Most people, particularly foreigners, get the recipe wrong from the very start, purists insist. Instead of spaghetti, they say it is tagliatelle that should be cooked to go with the rich meat and tomato sauce, making it "tag bol" rather than "spag bol".
"Along with lasagne, spaghetti bolognese is the most abused Italian dish. There are some crazy versions out there," said Massimo Bottura, a bolognese "virtuoso" who runs a restaurant in Modena. The worst he had ever eaten was in Bangkok. "It was terrible," he told the Corriere della Sera newspaper.
Abominations such as turkey mince, American meatballs, butter and cream have no part in a true spaghetti bolognese and need to be stamped out, say the guardians of Italy's culinary heritage.
"Abroad, when they offer spaghetti bolognese, it's often something that has nothing at all to do with the original," said Alfredo Tomaselli, the owner of Dal Bolognese, in Rome's Piazza del Popolo, who counts among his past customers George Clooney.
It is not only spaghetti bolognese that is subject to abuse in the kitchens of the world.
Other Italian dishes that have gained worldwide popularity, such as spaghetti carbonara, Neapolitan pizza, pesto and the creamy dessert tiramisu, have also been compromised, often with results that are close to inedible.
"It is always the great classic recipes that get most twisted around," said Alessandro Circiello, of the Italian Federation of Chefs.
RECIPE: The perfect bolognese
Serves four people
2 tbsp olive oil
6 rashers of streaky 'pancetta' bacon, chopped
2 large onions, chopped
3 garlic cloves, crushed
2 carrots, chopped
Stick of celery
1kg/2¼lb lean minced beef
2 large glasses of red wine
2x400g cans chopped tomatoes
2 fresh or dried bay leaves
salt and freshly ground black pepper
800g-1kg/1¾-2¼lb dried tagliatelle
freshly grated parmesan cheese, to serve
1. Heat the oil in a large, heavy-based saucepan and fry the bacon until golden over a medium heat. Add the onions and garlic, frying until softened. Increase the heat and add the minced beef. Fry it until it has browned. Pour in the wine and boil until it has reduced in volume by about a third. Reduce the temperature and stir in the tomatoes and celery.
2. Cover with a lid and simmer over a gentle heat for 1-1½ hours until it's rich and thickened, stirring occasionally.
3. Cook the tagliatelle in plenty of boiling salted water. Drain and divide between plates. Sprinkle a little parmesan over the pasta before adding a good ladleful of the sauce. Finish with a further scattering of cheese and a twist of black pepper.