S2, E5: Three celebrity chefs who cook the food of their ancestors discover family members who have shaped their lives — and America’s cuisine. Tom Colicchio of “Top Chef” learns the hardships his family endured (famine, bandits) living in a tiny town in Northern Italy and celebrates the courage of his original immigrant ancestor, a man who crossed the Atlantic many times to bring the Colicchios to the United States; Ming Tsai, the child of immigrants who fled Mao’s Cultural Revolution, was raised to believe that his that his family’s Chinese past was obliterated by the Communists — instead, he finds that his roots can be traced back more than 2,000 years, yielding a large family tree; and Aaron Sanchez discovers that his family’s treasured Mexican roots include people who were Spaniards, Africans and Native Americans.