I think there are many scientific publications. For Health Canada, it has to be peer-reviewed, first of all. That means it has undergone the scrutiny of scientists who are experts in that field, so it has to be in a peer-reviewed journal.
One study doesn't make conclusive evidence. We use an expression in Health Canada, “the weight of evidence”, which is looking at all of the studies out there. Is something reproduceable? Has it been reproduced in another lab? If one group of scientists does it, it's usually not considered conclusive until others can repeat it in different laboratories. Is the quality of the science there? There are different factors like that. It goes through scientific scrutiny.
Does that help?