By AMANDA POPE Staff reporter Undercover work by journalists is justified only if there’s a compelling public interest and no other way to get the story, says the Toronto Star reporter who recently posed as a temporary worker at a large industrial bakery. Sara Mojtehedzadeh, who covers labour, precarious work and poverty issues for the Star, said it was difficult to get temp workers at Fiera Foods to talk about their experiences on the record so, to get the story, she went undercover in May 2017 as a temp worker in the Toronto factory. “As journalists we have an ethical…