can doug ford order mandatory testing for agrifood workers?

no. sec 7, clearly.

however, the federal government can make periodic mandatory testing a work visa requirement and challenge the courts to undo it. it would no doubt fail an oakes test (that is, the oakes test would conclude that a breach is justified). so, this is one of those scenarios where the federal government breaking the rules on purpose could actually lead to a useful clarification of the rules, moving forward. this is the nature of our peculiar type of easily suspendable constitutional law - the government has to be willing to push loopholes.

if you want to look doug ford in the eye and give him a clear answer he understands, tell him it's out of his jurisdiction - but that the feds can effectively do it.