On a sweltering summer afternoon in Milan, Japanese food enthusiasts meandered through the marble-lined halls of the Palazzo delle Stelline, a 17th-century landmark that faces the church that houses Leonardo da Vinci's "The Last Supper." Inside, a group of Italians dressed in yukata (summer kimono) stopped to sample freshly griddled takoyaki (octopus dumplings) at a booth, while diners in the cafe browsed shelves displaying Japanese products such as green tea and rice crackers. From late June to mid-July, the Stelline had been the site of Salone del Giappone, an exhibition devoted to the cuisine and culture of Japan, which was sponsored by the Ministry of Agriculture, Forestry and Fisheries as part of the Expo Milano 2015 world fair, which runs through Oct. 31.