polenta

Northern Italy; coarse maize meal cooked slowly with water, which replaced earlier porridges of millet, spelt and chestnut after maize arrived from the Americas

Maize reached Italy in the sixteenth century and became the staple of the northern poor; reliance on it without nixtamalisation caused pellagra epidemics into the twentieth century

Northern Italy took maize and left the technique behind. Mesoamerican cooking treats the grain with alkali, which releases niacin the body cannot otherwise reach, and Europe skipped that step. Pellagra followed: in the Veneto in 1881 there were more than 55,000 cases among just over a million agricultural labourers. Cesare Lombroso gave decades to it and concluded it was a fungus in the maize, which it was not. But the Italian reckoning since is blunter than the missing-knowledge story, and it is worth taking: pellagra was a disease of poverty rather than of polenta. Maize eaten beside other food did not cause it. Maize eaten because there was nothing else did. So the crop crossed without its method, and then landed on the people who had no margin to absorb the difference. Two failures, and the second one chose who the first one killed.