At the beginning of last week, as Simon Laroche, the president of Kraft Heinz Canada, gathered with his senior executive team in Toronto to hash out a plan for how to respond if U.S. President Donald Trump slapped tariffs on Canadian exports, they realized they had to confront some vexing misinformation about the national identity of cream cheese. More than 70 per cent of the products sold by Kraft Heinz in Canada are manufactured domestically by Canadian workers, Mr. Laroche explained in an interview on Monday. But as fear and uncertainty descended across the country, some employees in their Montreal...