The 85-year-old woman who wants to collect every recipe in the world

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Harvard Food Historian Barbara Ketcham-Wheaton is trying to collect every cookbook ever published in Europe and the U.S. in order to compile an online digital database of recipes she's calling The Sifter. Her ultimate goal is to gather recipes from all over the world in the hope it will reveal the global patterns in cooking over time. She talks to the BBC's Emily Thomas. (Photo credit: Harvard University)