MILAN (AP) — A judge from Guinness World Records has certified a 122-meter-long (400-foot-long) baguette baked at the Milan Expo 2015 World's Fair as the longest in the world.

Some 60 French and Italian bakers worked nearly seven hours Sunday to bake the French bread characterized by its soft middle and crusty exterior, methodically moving a specially designed portable oven along the length of the doughy preparation.

The bakers worked at a rate of 20 meters (66 feet) an hour, their progress complicated by working outdoors and the biggest challenge to avoid any breakage.

"It's very difficult to do a big baguette because we are outside, you know, the temperature, it's cold and we are outside so for the dough it's not easy," said Dominique Anract, one of the bakers and owner of the La Pompadour bakery in Paris. Putting a plastic cover over the dough helped.

The Italian maker of Nutella, Ferrero, backed the enterprise to beat the 111-meter (364-foot) record held by a French supermarket chain. Once certified as a record-breaker, the baguette was cut and smeared with Nutella to share with the hundreds of Expo goers who celebrated the record.

It was at least the fourth world record declared during the six-month Expo, which closes Oct. 31, including the longest pizza at 1.5954 kilometers, or nearly a mile long.