“Top Chef’’ is headed to Boston this spring, but before it does, one of the Bravo show’s alumni will visit Cambridge’s MayFair on Sunday. “Top Chef Masters’’ and “Top Chef’’ season 5 contestant Fabio Viviani will be onboard the Columbus Foods’ MeatUp Food Truck on Sunday from noon until 6 p.m. at the 31st annual Harvard Square MayFair, spreading his knowledge of high quality deli meats.
