The issue is an important one. In our public health legislation, when we have reasonable and probable grounds that a hazard may exist, it allows our medical officers to act. That means, then, that one has to have some evidence to move--you can't just go about and be casual--but one has the ability to say that you should take steps to curtail, as soon as you can, the exposure of the public, or a portion thereof, to a presumed hazard until you investigate that one adequately.
So waiting until one has evidence beyond doubt, which may be useful for litigation purposes, is often too late to protect the public. The public expect, first, to be warned to take precautions. Then we can do the investigation to satisfy, when it requires, further litigious-type activity, if it were to take place.
So Dr. McKeown's answer would be correct: medical officers can close facilities, stop the sale or use of materials, or hold on to it in order to stop, in their minds, a potential hazard, if there are some reasonable grounds that the public would be exposed to a hazard, even if it's not fully known yet, because you need to take that time to investigate that.
It is important to understand the difference between that and waiting until you have all the evidence before you can carry out the action accordingly. The public's protection is paramount.
At that stage, I think that's the difference. When you have an outbreak that switches from being the industrial aspect to being the public's protection first and foremost, that other side can be looked after. But one needs to still coordinate with those so that there is some sense of coordination and communication. You don't do it in isolation as you're carrying out your investigation.