In the interest of open and honest communication, no one from the federal government will say why Mexican officials quietly inspected six Canadian slaughterhouses last year, part of an audit related to what one company called a border “issue.”

The Globe and Mail got confirmation of the inspections as Prime Minister Stephen Harper makes his first official visit to Mexico. Representatives of Canada’s beef industry are among those who have joined Mr. Harper on the trip. Industry and government officials were reluctant to discuss the unpublicized inspections, but one major beef producer, Cargill Inc., said six facilities were inspected by Mexican officials in October as part of a “beef plant audit,” including Cargill’s beef plant in Guelph, Ont. The reason remains unclear.

“This situation was not related to food safety,” Cargill spokesman Michael Martin said, referring questions to the Canadian Food Inspection Agency (CFIA). The agency confirmed inspections took place, but gave few details.