The maximum residue limits are standards that Health Canada is developing related to pesticides, antibiotics, heavy metals, and those types of contaminants. They apply to a product that is imported or produced in Canada. So an apple coming from New Zealand or elsewhere, for example, would be tested for pesticides, and the limit for certain pesticides in the food and drugs regulations would be applied.
If it contained a pesticide that was not allowed in Canada, it would not be approved. If it contained a pesticide that was allowed in Canada but exceeded the maximum residue limit, that product would not be allowed either.