Industry insiders are concerned that the federal government’s vaccine mandate on cross-border truckers will worsen the already strained supply chains, leading to shortages at grocery stores. “Ottawa’s plan to require all truckers entering from the United States to show proof of vaccination starting Jan. 15 cannot happen at a worse time,” said Sylvain Charlebois, professor and senior director of the Agri-Food Analytics Lab at Dalhousie University, on Twitter on Jan. 10. “I’m not sure Canadians are aware of how fragile our food supply chain is right now, due to Omicron.” The Liberal government announced in mid-November that truck drivers coming into Canada would need to be fully vaccinated by Jan. 15. Up until then, truckers have been exempted from the mandate as they are considered essential service providers. But on Jan. 12 evening, Canada Border Services Agency spokeswoman Rebecca Purdy told The Canadian Press that Canadian big-riggers will not have …