Where can I access statistics for the number of botulism outbreaks in Canada in recent years (anything from 2005 onwards)?
The quickest place to find information like this would likely be with CIHI. The STC data holdings on morbidity is limited. CIHI does have botulism listed in their classification of diseases, however, you'll have to search around in their tables to find the incidents.
These sources may also help you:
The PHAC website states that: “While outbreaks of food-borne illnesses in Canada are relatively common, botulism outbreaks are quite rare. In recent years, about two cases per year have been reported in Canada.” <http://www.phac-aspc.gc.ca/fs-sa/fs-fi/botulism-eng.php> (Under Surveillance tab).
There's also: Estimates of Food-borne Illness in Canada which provides the number of cases caused by a list of 30 known pathogens, one of which is botulism. <http://www.phac-aspc.gc.ca/efwd-emoha/efbi-emoa-eng.php>